Inspection Procedure 12

INSPECTION PROCEDURE 12: Gear Noise

NOTE: Noise from the engine, muffler vibration, transmission, propeller shaft, wheel bearings, tires, body, etc., is easily mistaken as being caused by malfunction in the differential carrier components. Be extremely careful and attentive when test driving, etc. Test methods to confirm the source of the abnormal noise include: coasting, acceleration, constant speed driving, raising the rear wheels, etc. Use the method most appropriate to the circumstances.

DIAGNOSIS

STEP 1.Check the tooth contact (engagement) of the drive gear.
Q: Is the tooth contact (engagement) of the drive gear correct?
YES: Go to Step 2.
NO: Adjust or replace the part. Then go to Step 9.

STEP 2.Check the drive gear backlash.
Q: Is the drive gear backlash correct?
YES: Go to Step 3.
NO: Adjust the backlash. Then go to step 9.

STEP 3.Check the drive pinion turning torque.
Q: Is the drive pinion turning torque correct?
YES: Go to Step 4.
NO: Adjust the turning torque. Then go to Step 9.

STEP 4.Check the drive gear and drive pinion for tooth damage or breakage.
Q: Are the drive gear and drive pinion for tooth damaged?
YES: Replace the part. Then go to Step 9.
NO: Go to Step 5.

STEP 5.Check the drive pinion bearing and side bearing for seizure, damage or breakage.
Q: Are the drive pinion bearing and side bearing damaged?
YES: Replace the part. Then go to Step 9.
NO: Go to Step 6.

STEP 6.Check the limited slip differential case assembly for damage.
Q: Is the limited slip differential case assembly damaged?
YES: Replace the part. Then go to Step 9.
NO: Go to Step 7.





STEP 7. Check the oil level.
Remove the filler plug and check the gear oil level.
Q: Is the gear oil level more than 8 mm (0.3 inch) below the bottom of the filler plug hole?
YES: Refill Hypoid gear oil API classification GL-5 or higher, SAE viscosity Number 90, 80W. Then go to Step 9.
NO: Go to Step 8.

STEP 8. Check that Hypoid gear oil API classification GL-5 or higher, SAE viscosity Number 90, 80W is being used.
Q: Is the Hypoid gear oil API classification GL-5 or higher, SAE viscosity Number 90, 80W. being used?
YES: Go to Step 9.
NO: Replace the oil. Then go to Step 9.

STEP 9.Check symptoms.
Q: Is the gear noise eliminated?
YES: Diagnosis is complete.
NO: Start over at Step 1.