and Gears

Clutch Control The Clutch is basically made up of two plates. One of them turns all the time the engine is running, the other is linked to the - drive shaft – real wheels and is moved only when touching the first one.

When the clutch pedal is in its normal (up) position the plates are held firmly together so that the engine will drive the truck. Pushing the pedal down separates the plates and breaks the link between engine and wheels.

To get the truck to move smoothly, the gap between these two plates has to be closed – but not too suddenly. This means letting the clutch pedal up until it reaches the point at which the two plates begin to come together, i.e. the friction point or balance point. With practice and experience you will know just where it is. You will be able to feel it and also hear it, because the speed of the engine and the tachometer will drop. Being able sense and locate the friction point is the secret of clutch control. The other part is being able to control the rest of the upward movement of the clutch pedal so that the two plates fit together without a jerk.

For changing gears when moving - the clutch is only pressed passed the friction or balance point (usually halfway in).

N.B. Only use half clutch on standard changes when moving.

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Clutch (Crashbox only) The clutch brake is used to stop the rotating parts of the gearbox. It is used only when stationary and clutch must be fully depressed before clutch brake is activated. The clutch brake needs to be held in between 2-5 seconds depending on how fast the gears were spinning before activation.

Double-Clutching (Crashbox only) Double-clutching (also called a double declutching) is a driving procedure primarily used for vehicles with an unsynchronized . These transmissions are sometimes called sliding mesh transmissions or crashboxes because of the difficulty in ​ ​ changing gears and the loud grinding sound that often accompanied. (NB: truck drivers in unsynchronized manual transmissions will often not use the clutch at all when driving but for the purposes of a driving test you must use the clutch).

The double clutching technique involves the following steps: 1. The throttle (accelerator) is released, the clutch pedal is pressed, and the gearbox is shifted into neutral. 2. The clutch pedal is then released, the driver matches the engine RPM to the gear RPM either using the throttle (accelerator) (when changing down) or waiting for RPM to decrease (when changing up) until they are at a level suitable for shifting into the next gear. 3. At the moment when the revs between engine and gear are closely matched, the driver then instantly presses the clutch again to shift into the next gear. The whole maneuver can, with practice, take no more than a fraction of a second, and the result is a very smooth gear change.

If you have not changed gears using this technique prior to training, do not be alarmed. We have trained many people from scratch who have successfully passed a driving test and gone on to work in the transport industry.

Double Clutch Technique Up Gears (Crashbox only) It is sufficient to allow the gear lever to rest momentarily in neutral and no “rev” is applied. The whole thing can, with practice, take no more than a fraction of a second.

The Action: (clutch in) gear to neutral (clutch off) (clutch in) engage gear (clutch off)

The Technique: 1) Take slack out of gear lever (purpose to aide knocking gear to neutral on time and physically and mentally prepare hand shift to next gear) 2) Attain correct truck speed truck ready for change 3) Clutch in, gear lever to neutral and clutch off 4) Clutch in, gear lever to gear and ease out clutch

Double Clutch Technique Down Gears (Crashbox only) To perform a double clutch, the clutch is pressed and the gearbox shifted to neutral gear. The throttle is ‘revved’ which applies power to the disengaged gearbox, thus speeding it up internally. The clutch is pressed a second time and the gear lever moved to the desired gear. The clutch is released again, driving continues.

The Action: (clutch on) gear to neutral (clutch off) (rev) (clutch in) engage gear (clutch

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The Technique: 1) Attain correct truck speed ready for change 2) Clutch in and knock out of gear and clutch off 3) Gently move gear level left or right to correct position in neutral 4) Rev motor 5) Clutch in 6) Place gear lever into gear 7) Ease clutch out

Some more details about changing down gears: ● When changing down gears one must “rev” the engine before engaging the next gear. ● Foot must be off the clutch when “rev” is applied. ● If you do not “rev” the engine high enough – the truck will reject the next gear. ● If you “rev” the engine too high – it will grind at first but once the tacho/speed drops to the right spot – it will then fall into gear

Diagram about “rev” during down shift Consider Mr “Rev” leaping up onto the gear changing cliff… how does he do it?

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Changing Gears on Hills with the Roadranger Gearbox

Changing Up Gears – Down a Hill ● Take off in a higher gear ● The hill (i.e. gravity) will cause the truck to speed up more quickly than normal ● Skipping gears may be the best option ● If changing up each gear 3 to 4 to 5 – then be sure to change gears quickly… the steeper the hill… the quicker the gear change must be ● Be sure not to accelerate or speed up too much before a gear change

Changing Down Gears – Down a Hill ● First and foremost be sure to slow the truck speed with the ● Truck speed must to slowed enough so the lower gear can be engaged ● Once the clutch is pressed and neutral is engaged during the course of a normal gear change – gravity will take effect and the truck will increase in speed ● The ‘rev’ needs to be increased to compensate for the increase in speed during a gear change… the steep the hill the higher the ‘rev’

Changing Up Gears – Up a Hill ● Be sure to speed up/accelerate enough to engage the next gear, the truck speed will slow because of gravity during a gear change ● Gear changing should be slightly slower than normal ● Do not skip gears ● Using the slitters and splitting gears may be the best option

Changing Down Gears – Up a Hill ● Gravity will slow the truck speed during a gear change so be sure to keep the speed of the truck higher prior to a gear change, compared with on a flat surface. ● Keep the ‘rev’ short and sharp and engage the gear quickly before the vehicle slows too much

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Gear Selection The ability of a vehicle to perform its tasks is based on the efficiency of its engine. When engines burn fuel, energy is released, but this cannot be used effectively unless the engine's power is managed properly. The driver is responsible for this management, by recognising and using the engine's ability as defined by its manufacturer.

Heavy vehicle drivers must select an appropriate gear, according to the engine speed required to complete the demands placed on the vehicle. There is a limited range of engine speeds (RPM) which produce high torque (force) and good fuel economy. Gears are designed to achieve the best engine speed which improves the use of fuel and reduces wear on the engine.

Manufacturers specify the engine RPM range for maximum torque. When accelerating or climbing a hill, you should usually up-shift or down-shift whenever the engine is approaching the limit of the RPM range. On a relatively flat road, where maximum pulling power is not critically important, you should select the gear which enables the engine to run at its most economical speed. This engine speed may be specified by the manufacturer, and may be slightly above the range specified for maximum torque. Experienced drivers may use the sound and feel (i.e. vibrations) of the engine as guides to gear shifting.

Using the Gears The way you use your gears has a big impact on your driving experience. Skillful use of the gears depends on accurately matching the gear to the road speed, and using the clutch and accelerator precisely. Your vehicle can only increase speed if the engine can deliver the power. It can only do this if you are in the right gear. You should aim to: ● Be in the correct gear for every road speed and traffic situation make all gear changes smoothly ● Engage a chosen gear without going through an intermediate gear first ● Know the approximate maximum road speed for each gear of the vehicle

To make rapid progress you should accelerate up to the engine's peak performance point and then change to a higher gear. You therefore need to know the manufacturer's peak engine performance recommendations for your vehicle. This may differ from both the maximum torque and the maximum revs obtainable from the engine.

The main effect of the gears is to transform speed of turning into power of turning and vice versa. ● The bottom or low gears produces plenty of power but relatively little speed; ● The top or high gears produces plenty of speed but at relatively low power.

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