Manual transmission driving technique

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Contents 1 Disclaimer 2 Beginning drivers 3 Theory 4 Learning to drive with a manual transmission 4.1 Shift patterns 4.2 Basics 4.2.1 Starting the engine 4.2.2 Moving 4.2.3 Stopping in first gear 4.3 Shifting 4.3.1 Upshifting 4.3.2 Downshifting 4.4 Starting on an upslope 4.5 Putting it All Together 4.5.1 Sharp Turns 4.5.2 Slow-Moving Traffic 4.5.3 The Canceled Stop 5 Troubleshooting 5.1 Stalling 5.2 Stalling due to loss of traction while braking 5.3 Grinding Gears 6 Advanced techniques 6.1 Easing out of gear (no clutch) 6.2 Power shifting (a.k.a. speed shifting) 6.3 Heel-and-toe 6.4 Double clutching 6.5 Single clutching 6.6 Shifting without the clutch 6.7 Starting the vehicle without an electric starter 6.8 Compression braking 6.9 Rapid off-the-line acceleration 7 Fuel efficiency 8 References

Disclaimer

Please note:

• This article only applies to cars and trucks equipped with a manual transmission, not to motorcycles or many types of quad bike, which also have manual transmissions but are operated using different techniques.
• This article is intended only as a helpful guide, and is no substitute for practice or training by a qualified instructor.
• Some countries prohibit operating a manual transmission vehicle to those who received their driver's license with an automatic transmission endorsement based on the type of vehicle used for the road test -- those people might have to take extra classes and an additional road test to legally drive a car with a manual transmission. [AUS, all EU countries and at least some Provinces of Canada]
• The extra wear on a vehicle's clutch inevitably caused by a new manual transmission driver is likely to reduce its service life by at least a few hundred kilometres.

Beginning drivers

Driving a car or truck with a manual transmission can be daunting for beginners. In addition to the usual physical and mental skills required to drive any vehicle, a manual transmission beginner must learn to contend with an additional hand control (the gear selector), an additional foot control (the clutch pedal) and a lot more concentration, at first, on what various systems in the vehicle are doing.

Many North Americans would caution new drivers against attempting the additional burden of learning to operate a manual transmission until they have mastered the more basic driving skills involved in driving any vehicle by practicing in a car equipped with an automatic transmission. In Europe, almost all learner drivers start with manual transmission cars, but they may choose to learn to drive with an automatic transmission instead -- for example if they're disabled, or if they find out they simply don't "get" manual transmission driving. However, such drivers will receive a driving license that is valid for automatic transmission cars only, and must pass a separate test before being licensed to drive a car with a manual transmission.

Theory

Internal combustion engines all share several limitations (compared to electric motors) that necessitate the use of some kind of transmission to make them practical:

• They develop little useful power at low engine speeds
• Their maximum speed is limited to a few thousand revolutions per minute, above which an engine begins to damage itself.

Due to these limitations, a hypothetical vehicle that had an internal combustion engine but not a multi-speed transmission would have a fixed ratio of engine speed to vehicle speed, and the range of speeds it could attain would be severely limited.

• If the vehicle had only a low forward gear, comparable to the first gear of a manual transmission, it would be easy to get it moving, and it would climb steep hills well. It would accelerate well from a standstill, too. However, it would have a very low top speed, making it impractical. Driving at 40 km/h in would waste fuel and wear the engine needlessly. Moreover, the ride would be jerky and uncomfortable, since even small modulations of the pressure on the accelerator would cause the car to speed up and slow down wildly. Such a transmission with a fixed low gear might be acceptable in a special-purpose vehicle which moves slowly, such as perhaps a lawn mower.

• A vehicle with only a low gear comparable to second gear would be mildly difficult to start, particularly uphill. It would be good at going up most hills, except at very slow speed or up very steep ones. For general shuttling around a residential neighborhood, this gear would be the best choice if there could be only one. In a typical manual transmission, second gear is the most versatile gear. However, it is too fuel-inefficient for driving on main roads and the severe limitation on top speed would make that vehicle impractical for freeway (highway, motorway) driving.

• If the vehicle had only a medium gear, comparable to third, it would be very difficult to start. Getting the vehicle moving would require a lot of clutch slip which would wear out the clutch, yet the acceleration would be poor. Starting against an incline would be impractical. Moreover, the clutch would have to slip or be disengaged for speeds below about 30 km/h, otherwise the engine would lug. It would be difficult to go slowly in bumper-to-bumper traffic, for instance, on level pavement, never mind uphill. Obtaining adequate power to climb steep hills at a slow speed would require clutch slip, in order to allow the engine to spin faster, yet deliver power to the wheels through friction on the clutch disk. And yet, third gear would be too low for fuel-efficient city and highway driving. Going merely 80 km/h in third gear would waste fuel, needlessly wear the engine and make a greater contribution toward air pollution. Between the constant lugging and the excessive RPM's, the engine would not last as long as it should, and the clutch would require frequent service.

• A vehicle with only fourth gear would be close to impossible to start, and useless for normal driving. In some cars, it's possible to drive in fourth gear at a speed as low as 50 km/h, but the engine may already show signs of lugging and won't be fuel efficient. If even a slight incline is encountered, a lower gear is required. About the same observations could be made about 5th gear, substituting 50 km/h for 60 km/h.

A transmission allows a vehicle to employ a variety of gear ratios in transmitting engine power to the drive wheels. Lower gears can be used for applying enough power to start quickly, for climbing hills and for acceleration. Higher gears can be used for cruising in a smooth, fuel-efficient way which prolongs engine life. Thanks to the multiple gear ratios, the clutch only needs to slip for a fraction of a second, when the car is started, and when the gear is changed, so a properly operated clutch can last for a hundred thousand kilometers or more, in spite of being a relatively inexpensive component.

In other words, the transmission with a multiple gear ratio is required for the internal combustion engine to be a practical source of motion for an automobile.

Learning to drive with a manual transmission

Beginning manual transmission drivers should avoid conducting their initial practice sessions on busy streets or in neighborhoods with many children, pedestrians or cyclists. In fact, it's best to start out in a large, deserted parking lot.

Shift patterns

A car or truck's shift pattern is usually indicated by a small diagram on top of the shift knob. For most five-speed transmissions it looks like this:

Image:Manual Layout.PNG

Another common five-speed shift pattern (often found in European vehicles) is:

Image:Manual Layout 2.PNG

In many BMWs, Volkswagens and all cars with six-speed transmissions, Reverse will appear in a different position, but the positions of the first through fifth gears are the most common used in the automotive industry. (Racing cars with non-sequential transmissions, and some high-performance passenger cars, use a different pattern that is better suited to high performance or race driving.) If you're unfamiliar with a car's shift pattern, study the shift pattern diagram until you're confident you know where first gear and reverse are located.

Neutral is often not indicated on the diagram, but can be selected by moving the shifter to the middle row between the odd- and even-numbered gears. Note that manual transmissions have no "park" setting. To park, the driver engages the parking brake with the transmission in neutral, then turns off the engine.

For extra security, especially when parking on hills, the transmission may be placed into first or reverse gear after the parking brake is engaged. It doesn't matter which one, although if the driver knows which of the two has a lower gear ratio, that one should be preferred, since it is in the lowest gear ratio that the engine will provide the most resistance to the movement of the car.

Some drivers follow a bizarre custom of parking in the gear opposite to the direction that the car would roll: reverse if facing downhill, and first gear when facing uphill. This does not provide any additional safety, since the engine will turn in either direction. The lowest gear provides the best resistance, regardless of the orientation of the car with respect to the slope. If anything, the opposite selection should be followed: using the gear which corresponds to the direction in which the vehicle would roll. This will rotate the engine's crankshaft, camshaft and attached components in the designed direction.

Basics

Starting the engine

First, the driver should engage the parking brake, or the main brake, or both, and then must always make sure that the car is in neutral before attempting to start the engine, by depressing the clutch pedal and moving the shifter to the neutral position. If the engine is started in gear a lot of strain will be put on the starter motor and the vehicle may lunge forward unexpectedly. The clutch is disengaged by depressing its foot pedal and is in an engaged state while no pressure is applied.

Many vehicles have a switch that automatically disables the starting circuit until the clutch is fully disengaged. In these vehicles it is necessary to hold the clutch pedal while starting. Some drivers prefer to do this in those without the switch also. It can be argued that this disengages the gearbox input shaft from the engine lessening the strain on the starter motor. However the engaged position is the resting position for the clutch mechanism. The clutch is disengaged by putting a large force on the trow-out bearing. This wears the bearing and the thrust washer that absorbs the end load, and it causes more friction than the transmission does, increasing the load on the starter and the battery.

Once the engine is running, the transmission is neutral until the driver is ready to move away. Either the parking brake, or the main brake, or both, remain engaged until that moment.

Moving

Starting off from a standstill can be one of the more difficult manual-transmission skills to master, but with practice it becomes second nature. The steps are: disengage clutch, select first gear, smoothly engage clutch while maintaining engine speed.

Because of their engines' limited torque at low engine speeds, most cars cannot start moving from a standstill by simply releasing the clutch pedal while in first gear--they will stall. Instead the engine speed must be increased via the throttle (using the gas or accelerator pedal) while the clutch is being engaged. The exception here is a diesel powered car, which can provide more power at low revolutions; here, it is often possible to move off from a stationary position (given the right conditions and vehicle setup) simply by slowly engaging the clutch.

The amount of throttle required to avoid stalling while starting out varies depending on the vehicle, but in general the engine should be turning between 1200-1500 RPM (indicated on the tachometer) while the clutch is being engaged. Too low an engine speed will cause as stall or a jerky start. Higher engine speed allows faster starts, at the expense of more clutch wear.

Beginners sometimes find the fine throttle control required to hold the engine speed within this range difficult. It helps to spend a little time practicing with the gas pedal, while the engine is running, the transmission is in neutral and the parking brake is engaged.

To start moving, the driver ensures that the clutch is fully disengaged by depressing the clutch pedal, then selects first gear. Having released the parking and/or footbrake, the driver then ensures that the engine is turning at the appropriate speed, and gradually engages the clutch by releasing the clutch pedal. If the clutch is engaged too quickly, the car will jolt forward, and likely stall.

By the time the car is moving faster than a brisk walking speed, the clutch should be fully engaged, meaning that the driver's left foot should be completely removed from the clutch pedal. The car is moving in first gear, which is rarely used for speeds greater than about 20 km/h (12.5 mph). It's probably best to practice starting and first gear driving in a large, deserted parking lot where the exercise won't impede other motorists.

Stopping in first gear

Coming to a stop in first gear is achieved by disengaging the clutch by pressing the clutch pedal all the way down with the left foot while applying pressure to the brake pedal with the other foot. The timing isn't important, except that if the clutch is still engaged when the vehicle gets below walking speed, the engine will probably stall.

When waiting at a traffic signal, it is better to take the car out of gear (into neutral) than to keep your left foot on the clutch, because the disengaged clutch wears somewhat and puts thrust and friction load on the engine. This is no longer important, as when European cars had graphite trow-out bearings, but it is till better for the car and for your foot.

A beginning driver who is confident starting, driving around and stopping in first gear is ready to explore shifting into the higher gears.

Shifting

For a given speed of travel, the engine speed will vary depending on which gear is selected. So, when you want to change gears, you need to pay attention to the difference between the speed the engine is turning in one gear, and the speed it will be turning in the next.

The difference in engine speeds between one gear and the next varies between vehicles, but in general lower gears will have a greater difference than higher gears. For instance, at 15 km/h (9.3 mph), the engine might be turning at 3000 RPM in first gear or 2000 RPM in second gear, whereas at 100 km/h (62 mph), the engine might be turning at 2800 RPM in fifth gear or 3200 RPM in fourth gear.

With practice, a driver becomes able to time shifts so that releasing the accelerator pedal, disengaging the clutch, shifting and then reengaging the clutch, and reapplying the accelerator pedal can all be done quickly without any jerkiness. Once again, it starts out difficult but becomes second nature with time.

Upshifting

When accelerating in any forward gear other than top gear, shift up when the engine is turning at too high a speed for the current gear. The engine speed that constitutes "too high" varies from vehicle to vehicle and according to the driver's taste, but the absolute upper limit is usually marked on most vehicles equipped with a tachometer as a red area called the redline. Running the engine past this speed can cause damage to internal components of the engine (and most modern cars with electronic engine control computers will not permit the engine to be run past the redline). In practice, one usually shifts up well before the engine speed reaches redline. The vehicle's owner's manual should contain a table of recommended upshift speeds, but as a general rule of thumb, consider shifting between 2000 and 3000 rpm - although in some small engines that make power higher in the rev band shifting around 3500rpm can drop you to a better part of the power band in the next gear. (Note that in a diesel you will usualy have to shift at a lower rpm, and the redline is likely to be lower.)

For maximum acceleration, one may shift just before reaching the redline, but for ordinary driving, to conserve fuel, one should shift between a little above the engine's maximum torque speed and the lowest engine speed possible without "lugging" the engine. With practice, you will be able to tell when to do this by the sound of the engine.

To upshift:

• Release the accelerator pedal. Alternatively, if you are experienced enough to shift quickly, you may be able to partially release and then reapply the accelerator pedal at the same time as declutching and shifting.
• Press and hold the clutch pedal with your left foot.
• Reapply throttle to a level appropriate for the higher gear. If you are experienced enough to shift quickly and smoothly, you may be able to partially release the accelerator pedal while shifting, and the engine will roughly synchronise. Alternatively if you shift quickly enough, reapply the throttle after reengaging the clutch.
• Move the gear shift knob, depending on the gear that is currently selected:
  • To shift from an odd-numbered gear (i.e. 1st or 3rd) into the next highest gear, move the shift knob down, through neutral, to the corresponding position on the bottom row.
  • To shift from an even-numbered gear (i.e. 2nd or 4th) into the next highest gear, move the shift knob up to neutral, one column to the right, then up to the new position on the top row.
• Smoothly release the clutch pedal, allowing the new, lower engine speed to match up with the vehicle's speed.

If you take longer than a second or so to upshift, the engine will probably have slowed down too much for the new gear, and the car will probably jerk backward a bit unless you increase throttle to compensate. Don't increase the throttle too much though, or the engine will be going too fast for the new gear and the car will jerk forward. Once your skill at "matching revs" improves you can release the clutch pedal more quickly without any jerkiness.

Downshifting

When decelerating in any gear above second gear, shift down when the engine is turning at too low a speed for the current gear. The speed that constitutes "too low" varies among vehicles, and you can afford to keep it in a higher gear if little acceleration is needed, but as a rule of thumb, consider downshifting when the engine reaches 1500 RPM. With some practice, you will be able to hear the engine speed and make this judgement.

Although rapid acceleration is never really necessary, it often saves time, can sometimes help to merge into moving traffic and is enjoyable to some people. For rapid acceleration or to climb as steep grade, while the car is already moving in a higher gear, one downshifts, to increase the engine's speed to a speed at which it can produce more power. (Beginners may prefer to stop and shift into first before climbing a hill.)

It is important not to shift into too low a gear for the car's speed. Downshifting increases the speed of the engine. If one shifts into a very low gear (e.g. second gear) at a very high speed (say, highway speeds) it is possible for the car's engine to be driven beyond the redline, conceivably causing severe damage to the engine. (In this case, even the engine control computer's rev-limiting function cannot help, as the engine is being driven by the momentum of the car). It is always safe to downshift to the next lower gear when the engine is turning at too low a speed for the current gear. If you "miss" a downshift and hear the engine revving too fast as you let out the clutch, immediately push the clutch back in and shift into a higher gear.

Due to the larger differences in gear ratio between first and second gear, it's usually best not to downshift into first gear unless you plan to be driving very slowly for some time. Instead, stay in second gear and disengage the clutch when you're about to come to a stop. In some special cases (very steep slopes, crawling traffic) first gear can be useful, however. In some vehicles, it is easier to shift into first gear from a stop than to downshift from second.

To downshift:

• Release the accelerator pedal, unless you are skilled enough to only partially reduce the throttle.
• Press and hold the clutch pedal with your left foot.
• Reapply throttle to a level appropriate for the current speed of travel in the lower gear. This is (somewhat) optional, since gradually releasing the clutch will adjust for a slight mismatch, however if you completely release the accelerator while at the same time shifting too slowly you are likely to have the car jerk somewhat.
• Move the gear shift knob, depending on the gear that is currently selected:
  • To shift from an even-numbered gear (i.e. 2nd or 4th) into the next lowest gear, move the shift knob up, through neutral, to the corresponding position on the top row.
  • To shift from an odd-numbered gear (i.e. 3rd or 5th) into the next lowest gear, move the shift knob down to neutral, one column to the left, then down to the new position on the bottom row.
• Gradually release the clutch pedal, allowing the new, higher engine speed to match up with the vehicle's speed.
• Adjust the throttle as necessary to decrease, maintain, or increase vehicle speed.

If you don't match the engine's speed properly for the lower gear, the car will probably jerk a bit. Once your skill at "matching revs" improves you can release the clutch pedal more quickly without any jerkiness.

Starting on an upslope

Decades ago, Studebaker invented and used a clutch-brake interlock mechanism called Hill-Holder™, which is currently (2004) available on Subaru Foresters. Most Mercedes-Benz vehicles, BMWs and some Volkswagens also hold the brake automatically until the clutch is at the friction point (sometimes called the biting point). Even without these aids, starting on a hill should be no more difficult than starting normally if proper starting technique is used.

The correct way to do this is to use the parking brake. When stopped on a hill, the parking brake should always be engaged (in a car equipped with a foot-operated parking brake, the driver must first select neutral and release the clutch, in order to be able to use their left foot to engage said brake). Then, the driver should (briefly) take their right foot off the footbrake, in order to ensure that the parking brake is effectively holding the car in place. The driver must not rely on the main brake alone, for safety reasons. If that braking system fails, or the driver's foot comes off the pedal for whatever reason, the car will start rolling backward. The parking brake and regular brake are distinct, redundant systems. If one fails, the other can still stop the car. For this reason, the parking brake is also called an "emergency brake", particularly in North America where most drivers own cars with automatic transmissions which have a separate and unrelated parking system built into the transmission itself.

To start, these steps are performed in rapid succession:

• Initial conditions:
  • the car is in neutral gear, stopped, and facing upslope.
  • The parking brake is engaged and latched with its ratchet mechanism.
  • The engine is running.
  • The driver's left foot is off the clutch, the right foot either on the footbrake or resting over the gas pedal.

• When ready to move, the driver presses the clutch all the way down and selects first gear.
• Then, the ordinary procedure for starting the car is followed: increasing the engine RPM by depressing the accelerator pedal, while slowly releasing the clutch. But of course, the car cannot move because of the parking brake.
• as the driver senses that the clutch is engaging and the car wants to move, they release the parking brake
  • if it is a handbrake, this means pulling the lever up slightly, depressing the button, then putting the lever down
  • if it is a foot-operated brake, it means pulling the brake release lever with one's hand
• ...while maintaining engine RPM and finish the starting maneuver as usual.
• the driver must expect that slightly more clutch slip will be required than when starting on a horizontal surface, and somewhat more engine throttle.
• the car may move anyway as the clutch starts to grab, because the engine power may overcome the force of the parking brake. This can be used to advantage. A hand-operated parking brake has a certain force range of its own which, with practice, can be incorporated into the technique.

Thus, essentially, starting on an upslope is much like the ordinary starting technique, with a correctly-timed release of the parking brake blended into the procedure.

Some manual-transmission drivers start on hills without using the parking brake, in spite of being experienced. This is wrong and shouldn't be done or recommended to others.

In fact, in some localities it is necessary to demonstrate mastery of the handbrake technique to pass a driving test.

It is possible to maintain your vehicle's position on an upslope without using the brakes by "riding the clutch" for short periods, namely using some throttle and modulating the clutch's engagement. In spite of being possible, this is damaging to the clutch and should never be done in regular driving, although it is often used to teach clutch modulation technique to beginners. A related technique which should also never be practiced is driving up steep hills at such a slow speed that, even in the lowest gear, the clutch is required to slip in order to maintain adequate engine RPM. If such a driving situation is expected to occur regularly, and cannot be avoided, the driver should consider owning a vehicle whose power train design supports that use.

Putting it All Together

In actual driving, the individually learned skills of modulating engine torque with the clutch and shifting gears are performed together. Decisions are made on-the-fly and sometimes they have to be canceled or pre-empted as predictions about traffic dynamics turn out to be incorrect. It takes several months of practice before the skills are nearly internalized, and anywhere up to a year of daily driving to become a completely smooth, confident, manual transmission driver who ensures that the machine is always in the correct state in every situation. These are a few tips beyond starting, stopping and shifting:

Sharp Turns

Situation: The driver wishes to turn at an upcoming corner. Coming to a full stop is not required.

Corners are taken at a fairly slow speed, which corresponds to the typical car's second gear: some 30 km/h or even slower. This means that accelerating out of the corner will require the transmission to be in second gear.

The steps are:

• The driver applies pressure to the brake pedal to slow the vehicle down, leaving the transmission in whatever gear it is in.
• Moments before approaching the corner, the car should be travelling at a speed in which second gear may be selected. The driver presses the clutch all the way to the floor and shifts into second gear.
• The clutch is released to complete the shift just before the steering is turned to execute the turn.
• Through the turn, the transmission remains in second gear.
• Coming out the turn, the driver begins to accelerate and straighten the steering.
• By the time the driver shifts to third gear, the car is travelling straight.

By avoiding a transmission shift in the turn itself, the driver can steer with both hands. In some countries or states—such as British Columbia, Canada—if a new driver takes a licensing road test in a manual transmission, points are deducted for shifting in a turn, because there are safety issues with doing so.

Slow-Moving Traffic

Situation: the driver finds himself or herself in a heavily congested flow of traffic. Sometimes the cars ahead come to a full stop. In between stops they sometimes crawl at approximately a walking pace, and at other times speed up substantially only to rapidly slow down again.

In this situation, stressful for a new manual transmission driver, it is important that the driver remain calm and focused. The driver must remember that to prevent the engine from stalling at any time, all that is required is to depress the clutch pedal all the way down.

The trick is to keep moving smoothly without allowing too great a gap to the next car, and stop and resume if necessary. It should all be done without slipping the clutch.

The driver should monitor the traffic as far ahead as visibility allows, to anticipate whether a complete stop is about to become necessary.

The driver should keep the transmission in second gear if possible and apply a light pressure to the accelerator pedal so that the vehicle slowly crawls forward. In first and second gear, particularly in first, the car is capable of moving very slowly without the engine stalling, or the necessity to slip the clutch. The manual transmission driver must learn to recognize situations in which it's useful to crawl slowly, and take advantage of the transmissions and engine's ability to do so.

But if an impending full stop is anticipated, the clutch is pressed all the way to the floor, and the other foot begins to brake. One of two events then happen:

• The car ahead in fact comes to a complete stop. After that, of course, the transmission must be put in first gear and an ordinary start must be performed, albeit this is probably very gentle start, since the car isn't about to accelerate anywhere fast! It's useful to practice slow starts in a parking lot, which is another situation in which they are useful. The goal is to quickly get the car rolling in first gear and let the clutch out all the way, but then remain at the low speed. This requires gentle throttle work to only maintain the RPMs a bit above idle during clutch engagement. As the clutch grabs, pressure on the accelerator stays light: it is not increased as would be the case if the intent were to accelerate.

• The car ahead does not come to a complete stop, but instead speeds up. Now, a decision must be made whether to release the clutch, stay in second gear, or to downshift to first gear. This depends entirely on the vehicle's speed and how much torque its engine has at very low RPMs. In time, experience with that particular vehicle will furnish the driver with the requisite intuition. (If the speed is very slow, less than about 5 mph or 8 km/h, it's possible to downshift to first gear in just about any car, even ones which can handle moving at these slow speeds in second gear). If downshifting to first gear is necessary, it is done without bringing the car to a complete stop. Releasing the clutch in this situation is different from releasing the clutch in first gear during a start from a complete stop. The clutch can be released much faster in first gear if the car is slowly rolling forward at about walking speed.

After downshifting to first gear, if that was necessary, the car can stay in that gear, with the clutch fully engaged. Very slow crawling can be achieved in first gear. Once the crawling is fast enough to take the engine RPM's into the 1500-2000 range, second gear should be selected once again. Again, anticipation of traffic ahead is very useful. If a cars are stopping ahead, creating a backward-propagating wave of stoppage, there is no point in switching to a higher gear. It's better to just continue to crawl in first, and then disengage the clutch and apply pressure to the brake when the stop comes. Better yet, if possible, the driver can allow the engine braking effect in first gear to create a larger gap to the next car, and use the space, together with the slow crawling capabilities of first gear, to avoid stopping entirely.

With practice, these shifts between first and second gear in heavy traffic become second nature, as will the traffic monitoring and anticipation which eliminates unnecessary stopping, shifting and clutch work.

The Canceled Stop

Situation: the driver is approaching an intersection where traffic is stopped at a red light. He or she is following the manual transmission technique for coasting to a stop. However, just as the approach is nearly complete, the light changes and it's not necessary to come to a full stop. The stop manoeuver is preempted, and a dynamic decision must be made about how to proceed. The key input to this decision is the vehicle speed, which determines what gear the vehicle should be in.

• If the vehicle almost came to a stop, and is rolling forward only very slowly less than 5 mph or 8 km/h, the driver may shift into first gear. At this speed, the driver should already have pressed the clutch all the way to the floor, in preparation for coming to a full stop. Because the car is rolling, the clutch can be released quite rapidly. (But if first gear is inappropriately selected at too high a speed, and the clutch is released rapidly, there will be a jerk!)

• If the speed is above approximately 5 mph or 8 km/h, but below around 20 mph or 30-35 km/h, the driver should select second gear, release the clutch fairly quickly and proceed.

• If the traffic change occurs above these speeds, resuming is possible in third gear. In fact, it's possible that the transmission is still in third gear and the clutch hasn't even been pressed down. In other words, it may be possible to just step on the accelerator and resume.

The tricky cases are the near-stops when the car is still rolling. The driver must select the correct gear based on speed, and be confident that a quick clutch release can be executed without stalling or jerking. The speedometer is of little use at these slow speeds. The driver, in fact, must not be staring at the speedometer and trying to reason about the correct gear. Rather, intuition for this must be learned through practice.

Troubleshooting

Stalling

When a vehicle's engine is turning at low speeds it is unable to provide much torque, and placing excessive demand on the engine will cause it to stop running suddenly, an event known as a stall. Stalling usually causes sudden jerking movements of the vehicle.

The following behaviours are likely to cause stalls:

• at a standstill, engaging the clutch too quickly, while the engine is turning too slowly;
• coming to a stop with the clutch engaged and the transmission in gear.
• trying to start from a standstill in high gear

If you stall the engine, don't panic. It happens to all beginners and even occasionally to experienced drivers, and it's nothing to be ashamed of. Just depress or keep depressing the main brake, step on the clutch, shift into neutral, start the engine up, and try again. If you feel like the engine is about to stall, step on the clutch. If you get scared or need to come to a stop, don't forget to step on the clutch while you're instinctively hitting the brakes, otherwise you'll probably stall.

The clutches in different vehicles vary in their sensitivity and range of movement, so even a very experienced driver in an unfamiliar vehicle can stall its engine a few times until he or she becomes familiar with its clutch.

Stalling due to loss of traction while braking

When decelerating, a driver will apply brakes and then disengage the clutch shortly before stopping (around 1000 RPM in 1st gear or somewhere above "walking speed" as above). In normal conditions with good traction, this is fine. However, on some surfaces, and depending on the severity of the braking, without an Antilock Braking System, the wheels can lock up. This can happen easily on slippery surfaces like snow, ice and loose gravel. The poor traction on such surfaces can prevent the momentum of the car from turning the wheels. The only real force for the brakes to oppose is the engine's.

When this happens, the first priority is to bring the vehicle safely to a stop or to regain braking and steering control. See also cadence braking, an important skill for winter drivers without ABS equipped vehicles.

Grinding Gears

A grinding sound coming from a synchronized manual transmission during a shift is usually a sign of improper technique. Some hobbyist drivers blame the machinery: they claim that the synchro mechanism is worn, or there is some issue with the manual transmission lubricant. This comes up again and again in online automotive forums. In fact, the synchro mechanism would have to be completely gone for this to be true, and it's almost certainly not an issue with the lubricant.

Why does grinding happen in a synchronized transmission? It's because the overly zealous driver engages the clutch too fast, in parallel with moving the gearshift, in an attempt to minimize the overall shift time. Or, perhaps the driver is doing everything in the correct sequence, but failing to press the clutch far enough! Either way, the gear selector has already "passed through" the synchronizer, but not gone far enough for the teeth to actually engage. At this point, if the clutch is engaged, even slightly, the speed of the input shaft will change, and the synchronization will be lost. Since the selector has already been pushed through the ring, it's too late: the stick can be moved so that the teeth make contact. The result is grinding.

Quite possibly, there could be a problem with the clutch: perhaps it is not disengaging all the way when the pedal is being pressed to the floor. The pedal might need adjustment, or there is some problem with the hydraulics or mechanical linkage, or other problem with the clutch mechanism itself. But here we are assuming that there is no mechanical problem.

To avoid grinding, do the waltz: think 1-2-3. On the count of 1, press the clutch all the way down to the floor. On the count of 2, move the stick to the desired gear. On 3, release the clutch. To speed up the gear change, you must speed up these motions individually, and not "cheat" by trying to overlap steps 2 and 3. There is little room for that. In particular, the lever must be in the final position before the clutch moves off the floor. Where you can save time is by tightly combining 1 and 2. Push or pull on the stick while pressing the clutch, to get it moving as soon as possible. Practice the waltz: count 1-2-3 in your head. Try doing it very slowly, and then speed up the tempo.

To do a fast gear change without grinding, push the clutch pedal to the floor as fast as possible, in advance of moving the stick, but start moving the stick even before the clutch hits the floor. The clutch should be all the way down as the stick passes through the neutral position to the other gear, and should remain floored. Move the stick as fast as possible from one gear to the other, using speed and force. You should feel a resistance followed by a click; that's the resistance of the synchro, which needs time to do its job before allowing the selector to proceed. Finally, release the clutch. This is the slowest part of the transaction, but with practice, it can be sped up significantly.

The common mistake that causes grinding is not moving the stick fast enough before releasing the clutch; failing to coordinate the two motions. Sometimes drivers complain about grinding during steep gear changes, when the engine is revved to a high RPM in the lower gear. The synchro has to do more work to slow down the input shaft of the transmission to match up the next gear! This takes more time, but the driver is not adjusting for it. He or she is not waiting for the lever to pop through the synchro, and is releasing the clutch using a rehearsed timing, independently of what is going on in the gearbox. The foot doesn't know what the hand is doing and vice versa! The foot must be trained to wait for the hand to complete the gear selection.

Follow these steps, and you will enjoy grind-free shifting in any situation, whether you are red-lining the engine in every gear at a track race, or lugging casually around town.

Another situation in which grinding can be heard is when placing the transmission into reverse from a stopped position, e.g., when leaving a parking space. Grinding occurs here in part because reverse is often not a synchromesh gear. If one does not leave the transmission in reverse or a forward gear when parked, it is likely that s/he will hear grinding in the transmission when shifting into reverse no matter how far the clutch pedal is held in when shifting. To avoid grinding in reverse, one must "clear the gate": first place the gear shift into a forward gear, then shift into reverse. This will eliminate any grinding that is heard. It works because all gears have the same speed when the car is stopped. On most 5-speed synchromesh transmissions, the gates will lock out a shift from 5th gear down into reverse as a safety feature; therefore, place the shifter into another forward gear before shifting into reverse. Some old cars have synchromesh on the upper gears but not on 1st, so this procedure should be used every time they are started from a stop. (Some old BMWs had synchromesh on first, for downshifts, but still crunched starting from a stop.)

One last note: the transmission oil can make a difference if the shift is being done improperly. A lubricant that doesn't have the proper friction additives will cause the synchro to take more time, giving rise to more opportunity for premature clutch release. This is why some technically inclined drivers report experiences like "I switched my manual transmission fluid from brand X to brand Y and now I get more (or less) grinding". Some cars also shift more easily when the transmission oil has warmed up; Mazda Miatas and VW Passat are particularly known for this.

Advanced techniques

This section discusses performance driving techniques, which may be detrimental to the life of the power train and other components of the vehicle.

Easing out of gear (no clutch)

It's possible to shift the transmission into neutral without using the clutch, and some of the other advanced techniques below call for this. However, taking the transmission out of gear may require a great deal of force, because the dog teeth are held in place by great torque between the input and output shafts. Pulling the teeth apart forcefully when they are jammed together by torque wears them. The force required is also demanding on the gear selector linkage and shift forks.

However, when the car is coasting to a stop, the engine eventually reaches a sufficiently low RPM at which there occurs a relaxation of the torque through the transmission. This relaxation can be perceived as a subtle change in the motion of the car; near a certain RPM value, the compression braking effect suddenly disappears, resulting in the sensation of a very slight forward jolt of the vehicle. This loss of the braking effect literally feels like a relaxation; the engine is neither propelling nor hindering the car's motion, because its idle speed is approximately matched to the rotation of the transmission's input shaft. In this condition, it may be acceptable to exert a light tug or push on the gear lever to see whether it can be gently coaxed out of gear. If it pops out easily, there is likely no harm done. On the other hand, if there is resistance, it can be relieved right away by pressing the clutch.

If the transmission remains in gear and the RPM drops further, the relaxation effect will disappear; the idle control mechanism will struggle to keep the engine turning, exerting torque on the slowing transmission. Sometimes the relaxation point is only very brief, or does not occur at all: for instance, when coming to a stop against an incline. The vehicle then decelerates due to gravity, regardless of the compression braking effect. Consequently, there will be only a tiny moment during which the transmission's speed will match the engine idle closely enough. The relaxation point may be located by exerting a continuous gentle force on the gear lever as the vehicle slows down.

Power shifting (a.k.a. speed shifting)

This is an advanced technique that gives a speed boost to the car when upshifting. This should only be used in racing applications, as it is very hard on drivetrain components, especially if done improperly. Even done properly, it generally puts undue stress on the drivetrain, and shortens the lifespan of the driveline components.

To perform a power shift, keep the gas pedal on the floor (instead of lifting) while pushing in the clutch. At the same time, quickly shift to the next gear. Quickly re-engage ("pop") the clutch as soon as the new gear is selected. If done properly, the car will receive a "bump" in acceleration (due to the jerk of the decelerating engine) as the clutch is re-engaged. If done improperly, it can result in engine or transmission damage, sometimes catastrophic.

Heel-and-toe

While decelerating, the technique of heel-and-toe shifting allows advanced drivers to maintain pressure on the brake pedal while simultaneously "blipping" the throttle to aid downshifts.

Double clutching

"Double-clutching" (also known as "double-declutching" in Europe) is an old technique that dates from before the days of synchromesh gear boxes. It can make downshifting (and arguably upshifting) smoother and can reduce transmission wear. It involves depressing the clutch and dropping into neutral, releasing the clutch, using throttle to match revs for the gear to be selected, depressing the clutch again and selecting the new gear. The action (which sounds more complicated than it really is) ensures that the output shaft is running at the right revs before a gear is selected hence creating smoother shifts and reducing wear on synchromesh systems. If the car is equipped with a tachometer, it may be used to help find the right engine speed. Some types of unsynchronized manual transmissions require double-clutching. These transmissions may be found in some older vehicles and race cars, as well as on large trucks, especially tractor-trailers.

Double-clutching on a synchronized gearbox is unnecessary in most driving situations. However, it is possible that an unskilled driver may second-guess something that the machine is designed to do automatically, and can cause more harm than prevent it. A true unsynchronized transmission is unforgiving to mismatched speeds, requiring a great deal of precision from the driver. A synchronized transmission will allow the driver to get away with sloppy double-clutching, and an unskilled driver may end up causing more harm by not matching the engine speed properly.

However, even with a synchronized gearbox, double-clutching under skilled hands is desirable when shifting down to the lowest gears. The synchronizer, particularly the one for the second gear, receives much abuse, as the speed differential it has to manage is usually the greatest. It is indeed usually the second gear synchronizer that fails first. Some recent Honda manual transmissions incorporate a triple-cone synchronizer in the lowest gears for extra durability.

Many transmissions until recently did not have a synchronizer on the first gear. It is therefore necessary to double-clutch when downshifting into the first gear, though such instances are rare. Some transmissions today still do not have a synchronizer for the reverse gear, requiring that you come to a complete halt before shifting into reverse (see the "Grinding gears" section above for further implications of this). Double-clutching is of course impossible, as you cannot reverse the direction of the engine rotation. You must simply wait for the car to come to a halt and engine revs to drop to idling.

Single clutching

A downshifting technique similar to a cross between double clutching and shifting without the clutch. The transmission is taken out of gear while the clutch is still engaged. The accelerator is then 'blipped' to bring the input shaft to the correct speed, the clutch is disengaged, the lower gear is selected and the clutch is engaged again. This is a fairly common racing technique.

Some drivers also use an even faster method than single clutch downshifting, which is also the method used in conjunction with heel-toe downshifting. The clutch is disengaged, the driver selects the new gear while "blipping" the throttle up to bring the engine to approximately right speed and then the clutch is engaged again. In other words, as the transmission's synchro changes the rotation of the input shaft during the gear selection, the driver simultaneously adjusts the engine revolution speed. The clutch can be released very quickly if the difference in rotation between the clutch disk and flywheel is small, so this gear change is likely the fastest technique on a synchronized tranmission. Some experienced drivers perform this revolution matching almost instinctively. During the downshift, as the gear selector passes between the gears, they hit the throttle to bring the engine revolutions up. The resulting gear change is not only faster, but it can be much smoother, as well as reduce the wear on the clutch.

Shifting without the clutch

It is possible to shift gears without using the clutch at all, by careful throttle manipulation. When transmissions were unsynchronized this was usually the easiest method, and still works in modern cars, although it requires a lot more practice than the usual methods described above.

Although the technique works in synchronized gearboxes, it is inappropriate in nearly all circumstances. A synchronized gearbox has a small clutch called a synchronizer (or "synchro") in every forward gear which brings the input and output rotation to the same speed before allowing them to engage. Like the main clutch, these synchronizing clutches use friction. These synchronizing clutches will allow for a margin of error when engaging without the main clutch. If the engine speed is somewhat too high or too low, the synchro will essentially take on the job that the fully engaged main clutch isn't doing. However, a synchro ring is not intended to do the job of a main clutch. Its job is to spin up or spin down just the input part of the transmission that is assumed to be disconnected from the engine. It is not intended to speed up or slow down the entire engine. Such experimentation done on a regular basis will prematurely wear out the synchro rings, which will have to be replaced.

On cars with a freewheel, such as the older SAAB with a two-stroke engine, shifting without the clutch is standard procedure. But actually, the freewheel is a form of clutch: one that is disengaged whenever the input rotation is slower than then output rotation. One must disengage the freewheel by allowing the engine revolutions to drop, which is analogous to pressing the clutch pedal.

Starting the vehicle without an electric starter

Should the starter fail to operate due to a dead battery, electrical fault, or bad starter, the vehicle may be startable via momentum. The energy to move the vehicle initially can be supplied either by gravity (if the vehicle is parked on a hill), or by people pushing. A winch will not operate fast enough to start the engine. Do not push the vehicle with another car or truck; the bumpers may slip, damaging both vehicles.

To start the vehicle on a hill if the vehicle is facing downhill: put the car in second gear and turn the ignition on, disengage the clutch, and release the brake. Wait for the car to reach about 10km/h, then release the clutch slowly, as if executing a steep downshift. The car will slow down due to compression braking as the engine spins up. If ignition and fuel are supplied to the engine, it will start. If it does not succeed the first time, try again with more speed. If it still doesn't work, whatever is causing the engine to not start is also preventing it from running.

The techniques for starting while facing downhill and push-starting are similar. A single person may be able to push-start a compact car or mini-truck; it may take several people to start a larger vehicle. Use reverse gear for starting while facing uphill.

Important notes:

• If the starter failure was due to a discharged battery, it will recur unless the engine runs long enough to sufficiently recharge the battery.

• If the starter failure wasn't due to a discharged battery, it will certainly recur. The car will have to continue to be push started, and must be taken to a mechanic to have the starter problem identified and repaired.

• The alternator in the car is not meant to charge deeply discharged batteries. A proper battery charger includes a current limiting circuit which "trickle charges" the battery. A deeply discharged battery places a load on the car's charging system. Put the battery on a trickle charger at the earliest opportunity.

• If the battery is completely flat, push starting may not work, because modern cars have an alternator which does not contain permanent magnets. It has coils which require a small field current to generate a magnetic field.

• Check the condition of the battery first. Some batteries have an hydrometer "eye". If the eye is green, dark green or dark, attempting to push start should be okay. If it's clear or yellow, indicating an insufficient fluid level, don't jump or push start. The battery needs distilled water, and should not be charged. If it's a sealed battery, it should be replaced, since there is no means to add fluid.

• If the battery is frozen, do not push start or jump start the vehicle. The battery must thaw first. Frozen batteries should not be charged.

• Read the owner's manual of the vehicle for any special instructions regarding jump starting, and follow whatever reasonably applies to push starting also.

• If the car has power brakes or power steering, these will not function during the push start until the engine starts. If the car is being started by rolling down a hill and the engine fails to start, a lot of extra brake pressure will be needed to stop it, and extra force on the steering wheel will be needed to steer around any obstacles.

• To start the car smoothly with the clutch, depending on speed its best to start in the higher gear so that engine revs won't soar too high when coming back alive again. Fuel economy pros use this technique to turn off their engine then putting the shifter into Neutral when acceleration is not needed, and then when a lower speed has been reached (say 30 mph or 50km/h) then one would attempt to restart the car with the clutch in 5th gear, since this method is much less harsh than turning on the engine with the key. One would have the clutch disengaged (clutch pedal in) and then from Neutral slide it into 5th. Then as you let rengage the clutch (slowly releasing to the friction point) you will feel it gripping the engine. Immediately let off the clutch pedal till the engine starts firing its cylinders and then right away press the clutch again to avoid aftershock. If done correctly within the second, the clutch should absorb any NVH (noise, vibration, harshness) and engine revs should rise to about 1100 rpms. If engine fails to start try a lower gear, but remember the lower the gear, the more clutch you need to absorb the greater aftershock. Engine revs could be higher during a bump start like 1500 rpms or 2000 although you want to keep these revs as low as possible in order to reduce wear and tear on the engine (rev too low and the engine won't come back on, one must know which gear to start with so that NVH is controllable for all speeds... in this case its harder to control as your momentum decreases). As the revs fall and settle to idle, one should rev match into the appropiate gear and then accelerate their way to desired speed (usualy 40mph or 70km/h before areodynamic losses are prevalant) and then repeat for maximum fuel economy. I suggest refining this technique before attempting to use in real world driving situations as if fallen to the wrong hands can be deadly (like speeding). A master with this technique can recall the engine within half a second and start accelerating as soon as that second is done with no NVH to either the driver or the passengers. And the mileage increases are reported to beat EPA highway estimates in the CITY. If one hasn't noticed why not just coast in Neutral? Simply because as your momentum decreases, the same amount of fuel used to keep the engine running won't be worth it as opposed to coasting with the engine off and mileage is still increased even at very low speeds. There is no payback for fuel coasting with the engine off as opposed to coasting with the engine on in Neutral. In Neutral one has to be travelling at higher speeds to gain the mileage benifits of coasting (since when one is in gear, engine braking prevents the car from travelling far with just momentum), but with the engine off that rule is broken and mileage soars upward at any speeds. Its just a matter of learning how to turn on one's engine when they need it the most as well as maintaining safety, passenger comfort and not overdraining your 12 volt battery.

Compression braking

This is also called "engine braking"; the use of the engine's internal resistance to slow down the vehicle, or keep it from accelerating down a hill. This is done by shifting the car into a lower gear and releasing the clutch, with the foot off the throttle.

Some feel that you abuse your manual transmission and engine by "engine braking". They feel that you should downshift only when you anticipate that the car will be in a lower speed for some time, not when coming to a full stop. Some feel that the reason why you must keep the car in gear while slowing down or stopped but with the clutch disengaged is for emergency manuevers, for it will give you the extra time to escape a pending accident. In this case, downshift late, allowing the car to slow to a pretty low engine RPM's before shifting down.

Using the manual transmission to stop the car is inappropriate under normal driving conditions. Simply put, when using the engine to slow the speed of the transmission, the clutch and synchronizers are unnecessarily being worn out for what the car brakes are designed to do. In comparison, the clutch typically costs around US$1000 to fix as opposed to US$300 for new brake pads and installation. The method is provided only because one may find it occasionally necessary or useful to use engine braking (when one needs to decelerate more quickly than usual, for instance).

If decelerating towards a full stop while in an upper gear, such as 4th, a downshift to a lower gear should be made, as this increases the time that a gear is engaged, therefore keeping the brake and power steering servos engaged and so power is supplied. Coasting time should be kept to a minimum using effective and well-timed downshifts.

On the other side of the coin, some feel that engine braking is relatively harmless to the engine and transmission. The idea is that during decceleration the engine creates a vacuum in the cylinders which pull a very small amount of oil past the rings, increasing protection. This, combined with the fact that the forces involved are typically less than those normally seen during acceleration lead some to conclude that it will make no real difference in the lifetime of the engine and transmission.

There is a situation when engine braking is truly called for: going down steep hills which are also very long, and for whatever reason, it is undesirable to pull over and stop the car. Braking downhill for a long time can overheat the brakes leading to failure. A combination of gearing down and using the brakes is safer. But heat can be dissipated from brakes also by pulling the car over and letting it stop for a while, effectively dividing the long hill into a sequence of shorter ones.

In fact, drivers find that most of the time, the best manual transmission driving practices closely mimic the actions of an automatic transmission, except in cases when the automatic transmission lacks anticipation of changing conditions. To be a good manual transmission driver, drive an automatic and observe what it does. Modern engine and automatic transmission control (such as that found in the 2005 Toyota Tundra) incorporate downshifting the automatic transmission out of overdrive during braking, or when the car is coasting down hill faster than the cruise control setting.

See compression braking for more information.

Rapid off-the-line acceleration

When drag racing or performance testing, the engine is revved to near its torque peak and held there with the clutch and throttle until the speed allows the clutch to be fully engaged without dropping below this engine speed. The extra engine speed can be absorbed either by the clutch or, in cars with sufficient power to weight ratio, by the driving tyres. Normal performance driving evolves a compromise between this and the gentle start-up described under Basics. A skilled driver should be able to chirp his tyres at will, in even a moderately powerful car, but should do so only in situations like merging into high speed traffic.

Fuel efficiency

See main article Fuel efficient driving.

Manual transmissions have an inherent fuel efficiency advantage compared to conventional automatic transmissions (the type that have a torque converter coupled to a planetary gearbox) because the torque converter, a kind of fluid-coupled clutch, wastes a percentage of the engine power. Many automatic transmissions have a locking mechanism which bypasses the fluid coupling by mechanically engaging the moving parts of the torque converter together; but this only happens when cruising in the overdrive gear.

To make the most out of the fuel efficiency advantage, a manual transmission car has to be driven in certain ways. Some things that manual transmission drivers do can waste fuel in ways that wouldn't happen under an automatic transmission.

The first general guideline is to shift earlier rather than later. Shift at the lowest RPMs in the current gear that will allow the engine to run without lugging in the next higher gear and that will supply sufficient power to accelerate or climb a hill at the desired rate. Shoot for a target of about 1500 to 2000 RPM in the next gear, when accelerating gently. This is especially true for diesels where the torque band peaks at lower RPM than in petrol engines. Remember that the engine's efficiency is greatest at near to is maximum torque speed, which is usually half to two thirds of it redline speed, in an overhead valve engine, and near to full throttle. Shifting below the torque peak or using less than full throttle may help somewhat, because is causes less variation in the engine's running condition between accelerating and cruising. But running the engine above its torque peak, or at a higher speed than is necessary to get the desired power, takes considerably more fuel.

Third, look for and anticipate stops and red lights up ahead. Whenever you have to bring the vehicle to a full stop, you are turning all of its kinetic energy into heat in the brakes. That energy has to be regenerated from the car's fuel in order to get moving again. Don't race toward red lights. In most modern, fuel-injected cars, if the car is in gear and coasting, no fuel is used. It is best to leave the car in gear while it slows, and then change to the correct gear when accelerating again.

When approaching a hill, slowly speed up the vehicle to build momentum before reaching the hill.

References

• "Your Mileage May Differ", Road and Track, May 2006, pp. 105–111.