S20 GEARBOX DIFFERENTIAL UNIT NOISY'/ / GENERAL - Alfa - 166 - eLearn

3308715 - S20 GEARBOX DIFFERENTIAL UNIT NOISY'/ / GENERAL

With the engine running and the vehicle moving, there is a noise from the area of the gearbox in all conditions.

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Carry out a preliminary test to check the conditions which give rise to the noise	General noise: Continue to Step 1	Noise during take-off	See table S21
			Noise in neutral	See table S22
			Noise in one gear only	See table S23
			Noise round bends	See table S24
1	GEARBOX/DIFFERENTIAL OIL LEVEL CHECK	All OK	Problems met	Operation
	Check the gearbox / differential oil level Op. 2110A04	Continue to Step 2	Level too low	Restore the correct level
2	CHECK GEARS	All OK	Problems met	Operation
	Overhaul the gearbox (see OVERHAULING GEARBOXES Assembly 2110B).In particular, check the gear teeth: they should not be worn or show traces of seizing	Continue to Step 3	Gears worn	Replace the gears involved
3	CHECK ON SYNCHRONIZER RINGS	All OK	Problems met	Operation
	Overhaul the gearbox (see OVERHAULING GEARBOXES Assembly 2110B).In particular, check the synchronizer rings: they should not show signs of wear on the internal surfaces.	Continue to Step 4	Seals worn	Replace the synchronizers
4	CHECKING THE CROWNWHEEL AND PINION	All OK	Problems met	Operation
	Check the crownwheel and pinion. (see OVERHAULING GEARBOXES Assembly 2110D) In particular: it should not be worn or damaged there should not be excessive clearance	Continue to Step 5	Reduction gear damaged	Restore the clearance or, if necessary, replace the crownwheel and pinion
5	HECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists	Search for the fault starting from another symptom'