[Cracked366]

Front diff went out last month, slowly started to grind. My fault not replacing the fluid, I run her pretty hard and have towed my trailer prob 20k miles. I found a donor Audi that Ebay said would be compatible, it sure fit, but the gear ratio has to be off. I thought we had it licked, ran smooth a few days normal commuting, but at high speed (accelerating past 80mph) or climbing a hill the 4motion engages and it shutters. Does anyone know where to find the bearings to rebuild it...the bad bearing is behind the conical spiral just off the main drive shaft. First problem would be how to remove it, seems like it's part of the main housing, my press would crack the housing if I went after it. I've seen some good write ups here on rebuilding the early model year differentials, haven't seen it on T3. Part is $3500 new or shipped used from Germany / Slovakia $1500. 😫

 

[Cracked366]

Its a 13 14 15 Q7 front diff, seems like the right fit...am I missing something else? Stepper motor or somethin...when I start out on a turn it jumps a bit..mostly under load, feel my front end hoppin climbin a steep hill or acceleration above 80.

 

[chewblekka]

What’s the part number on your original front diff, and on this one? What engine is it from? If the ratios are wrong you’ll damage your centre diff very quickly. For now I would remove your front driveshaft until you can repair it properly. Otherwise you’ll be replacing your transfercase too.

 

[Cracked366]

Yeah, I stopped driving it. Have a backup work truck. Considered removing the front shaft, good call. Ordered the right used part from a matching VW TDI. Ebay was wrong on fittment, shouldn't have trusted it. This new part does however fit an Audi Q7 11-12. The rebuild idea was abandoned since there are many salvaged diffs out there to swap in. Hope I didnt cause more issues already, definitely need fluid changes all around. Tranny was done at 100k but neglected the diffs and transfer case. Shame on me...it was neglect