Challenge #1
1. To clearly identify the nature of the noise, drive along the highway at a speed of approximately 20 km/h.
2. Then gradually increase the speed up to 90 km/h, listening at the same time for different types of noise and noticing the speed at which they appear and disappear.
3. Release the throttle pedal and, without braking, dampen the engine speed.
4. During deceleration, watch the noise change, as well as the moment when the noise increases. Normally, the noise comes and goes at the same speeds both when accelerating and when decelerating.
Test #2
1. Accelerate the vehicle to approximately 100 km/h, put the gearshift lever in neutral, turn off the ignition and allow the vehicle to roll freely to a stop; watch the noise pattern at different deceleration rates.
2. The noise noticed during the test and corresponding to that noticed during the first test does not come from the gears during the first test, since they cannot make noise when unloaded.
3. Conversely, noise noted on the first test and not repeated on the second may come from the gears of the gearbox or the bearings of the pinion or differential.
Challenge #3
1. With the vehicle stationary and braked, turn on the engine.
2. Gradually increasing its speed, compare the resulting noise with those seen in previous tests.
Attention! When turning off the ignition, be careful and careful. Do not turn the key more than necessary. This may cause the anti-theft device to operate.
3. Noises found to be similar to Test No. 1 will indicate that they are not gearbox noise during the test and are caused by other components.
Challenge #4
1. Noises detected during the first test and not repeated during subsequent tests come from the gearbox; raise the rear wheels to confirm.
2. Start the engine and shift into fourth gear.
3. In this case, you can make sure that the noises really come from the gearbox, and not from other components, such as suspension or bodywork.