audi 80 TDI 1994 gearbox excessive vibration trough the car

[8stud]

hi all,we have an excessive noise coming through the front of the car very noticable at low speeds but nearly dissapearing above 70 mph. The noise doesn't change when cornering but it sounds like a bearing noise.I checked wheel bearings/halfshafts /brake disks all in good order when i jacked and blocked the car up, both wheels of and of the ground, ran the car in gear and stoped one halfshaft turning let the diff do all the work,i could feel some grottines/vibration tru the shaft that i stopt turning,repeated the process on the other side with the same result/vibration when not turning.Conclusion not the half shafts/wheelbearings,it must be in the diff. Question,anybody out there with the same problem or sugestions and can the diff be dropped out the gearbox without removing gearbox from the car. Thanks. 8stud

[a8 tech]

The diff can be removed with gearbox in place.And yes it sound like you have a diff problem,but you will only find out when you strip.Advise you drain the oil first and look for any swarf,as this may indicate if any mechanical failure has occured.

[russA80]

I too have a diff problem but my just whines. It is getting louder to the point where I want to take action. Has anyone out there actually replaced the diff bearings. How easy is it, as I guess you need to shim the new bearings, but not sure how to do this and know it is correct

Many Thanks

Russ

[a8 tech]

You just refit the shim,no adjustment is required for diff bearings.I use to do these a lot and had no problems.