What to do with the candidate. 1. During the brief, get them to explain what the gearbox does and how they use it. This will demonstrate that they have (or have not) an understanding of their car. But you need to be prepared to tell them how it works if they do not know. We have had candidates with a Tiptronic gearbox who asserted that they had no way of forcing a low gear to be selected. 2. Make sure they do something when stopped in traffic. They should at least apply the handbrake, and should be capable of discussing the merits of D or N when in this situation. 3. Make sure they engage a low gear when going downhill, and at appropriate corners and hazards. 4. If they have Tiptronic, it is nice if they can do a period of driving the car in manual mode.

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 Candidates have to demonstrate appropriate usage of the auto gearbox on their test, just like manual drivers. We have to help them achieve this. The attitude of "just leave it in D" is incorrect and unhelpful. This guide aims to show you what to look for, and how to advise the candidate. Note this covers conventional and modern automatic gearboxes. It does not cover semi-manual or "clutchless" cars, nor does it cover the Daf “Variomatic” - later Volvo and Ford “CVT” (Constantly Variable Transmission) - system using a drive belt and two pulleys.

Version: 071130

Observer's guide to automatic gearboxes

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Basics All automatics have the same four basic positions for the selector:

Notes:

1. Autos have a torque converter which has a similar function to a clutch in disconnecting the engine from the wheels. It allows the car to be held stationary on the brakes while in gear, and allows smooth gear changes.

2. Older cars had just three forward gears. This is all that was needed since the torque converter was able to accommodate all necessary ratios. Modern cars may have many forward gears (currently up to seven!), thus the torque converter is not needed so much, and can spend most of its time fully engaged. This removes much of the inefficiency and poor performance that automatics are reputed to have.

3. Most cars will not start unless the selector is in P.

4. Most cars have an interlock so that you cannot move out of P unless the brake pedal is being pressed.

5. All selectors have a little button that you need to press to move from P or N into R or D.

6. In some cars you cannot insert or remove the ignition key unless the selector is in P.

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.When stopped in traffic for longer than a few seconds

The basic choice is to stay in D and use the handbrake, or to go into N and use the handbrake.

The IAM guideline is to leave the car in D and use the handbrake when stopped in traffic. The justification for this is that moving to N somewhat defeats the point of having the auto, and can put wear on the selector mechanism and gearbox in some cars.

There are several arguments against this:

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- This is not the same as being in gear with the clutch pressed in a manual car. The gearbox is making a very positive attempt to move the car forward.

- It uses more fuel than being in N.

- An accidental jab on the throttle, or a sudden increase in revs as the aircon turns-off, may overcome the handbrake and make the car lurch forward.

- Some cars have a strong “creep” when in D, and this may be enough to overcome the handbrake, or at least make it dangerous to just use the handbrake.

So Going into N may be safer.

Some cars (Volvo at least) may electronically put the gearbox in manual when the handbrake is engaged. This is fine and the best of all worlds.

P (Park) is like neutral - the wheels are disconnected from the engine, but are mechanically locked so that the car cannot move if the brakes are off.

R (Reverse) engages the single reverse gear.N (Neutral) is the same as in a manual car. The wheels are disconnected

from the engine, so the car can roll if the brakes are off.D (Drive) senses the road conditions and the driver's needs, and

automatically selects between the available forward gears.

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What to use when. As with a manual gearbox, different cars and different driving styles, mean that there can be lots of variation, so do not treat this as set in stone. Normally the selector will be in D. The gearbox is quite capable of doing sensible things in most situations, and this is why people buy an auto in the first place. So D is the default. P is only ever used when parking. The selector is never moved to P when stopped in traffic, at junctions, or at traffic lights. In these situations there is no need for P, and the reversing lights will flash (thus confusing other drivers) when the selector is moved past R. At Stop signs stay in D with the footbrake applied (to stop the car), but also apply the handbrake (to demonstrate that the sign has been seen). Observers should expect candidates to engage a low gear in the same situations as in manual cars. Things like downward hills, long bends and sharp bends are obvious situations where there is a need for more control through use of the accelerator.

It may also be desirable to engage a low gear in 30mph zones as with a manual.

Candidates should remember that, as with a manual gearbox, selecting a specific gear on an automatic box should take place when the correct speed for the hazard has been attained. As with a manual gearbox, secondary braking should be avoided.

There should be no need to engage a lower gear when going up hill, but some people have experienced automatics "hunting" between two gears when on an upward slope. This may just be a problem with an older less sophisticated gearbox

Older cars, and less sophisticated modern cars, usually have two positions in front of D allowing the driver to manually select and hold a low gear. The gearbox will not allow damage to be caused, so will not engage the lower gear until the speed of the car and the engine revs can be matched safely. Once in the lower gear, the gearbox will never change up to a higher gear, but will move freely down and back up to this gear.  For example, in a four gear car, selecting "3" will cause a downshift to third gear as soon as it is possible, and then allow changes between first, second and third as necessary. These positions are therefore good for (downward) hills and corners since they hold a lower gear. They will not help when trying to move off in ice and snow.

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Modern cars may have what is generally called a "Tiptronic style" gearbox. (Tiptronic is actually the VW/Audi name, other manufacturers call theirs something else ending in "tronic".) With all of these there is some way of moving the selector between positions marked "+" and "-" to go up or down a gear. When this is done the gearbox is in "manual mode”, and the gearbox will hold the selected gear for as long as possible. The idea is that you can now adopt a manual style of driving, moving up and down between the gears (but obviously without a clutch). The gearbox will still prevent damage, so will always override what you choose if necessary.

There will be a display somewhere on the dashboard showing which gear is currently engaged.  Moving back to fully automatic mode is achieved either by nudging "+" when in top gear, or by moving the selector back to D.

Extras.The gearbox may also have a Sports mode. In less sophisticated gearboxes, this may just move the gear change points to favour a lower gear. More advanced gearboxes will alter the whole shift pattern to aid enthusiastic driving, and may also be adaptive to the driver's style and how they use the accelerator pedal. "Kickdown" is the shift to a lower gear when the accelerator pedal is pressed hard. This used to be a switch that was activated at the end of the pedal travel, but nowadays computers sense the need for this in a much more advanced way, and the downshift is not the major event it used to be.