Gasoline powered, not governed
Start in low gear, using only enough power to place the vehicle in motion. Don't rev the engine up in this gear to maximum rpm, but shift to the next higher gear. Progress through each higher gear, increasing vehicle speed and engine rpm together. As each shift is completed, engage the clutch smoothly to avoid shock to the drive train, load and passengers.
Using an engine tachometer in shifting
Most engine manufacturers recommend 85% of governed engine speed to be the most efficient for normal operation of a vehicle. Knowing the governed speed, a simple calculation will give the most efficient operating speed. When driving, a glance at the tachometer will indicate the necessity of a change in gear.
All transmissions have a known split between gear ratios and knowing your transmission will give you the drop in revs required to make a clean shift.
Shifting down is also made easier by a tachometer. In reversing the above procedure, knowing the split or rpm difference between the gears, a driver will be able to increase the engine revs to make a clean downshift.
Shifting up through the gears (main transmission)
In each gear, sufficient speed must be built up to avoid labouring the engine in that gear; speed must be sufficient so the engine will not be laboured when the next higher gear is reached. Double-clutching should be used on most manual-shift truck transmissions. Shifting is faster and smoother when the double-clutch procedure of depressing the clutch twice with each change of gears is used.
Be alert to changing conditions which may require reduced speed and shifting to a lower gear. Don't wait until the engine starts to labour before shifting down. For dangerous downgrades, gears should be downshifted to make use of engine braking. A good driver will downshift before passing the crest of a hill because it's dangerous to downshift past that point. If you miss a gear you're in trouble.
In addition, if your brakes fail on a level road, you should shift to a lower gear and use engine compression to help stop the vehicle.
Your knowledge and ability to use the clutch and to select and shift gears, as would be required in the normal operation of the vehicle, will be observed during the road test.Previous page Next page