Has anyone seen a DIY for fixing a leaking center differential? I have a 1999.5 A4 Avant Quattro 1.8T. The differential is leaking more than before. I've been replacing gear oil, but I'd like to reduce the amount of leakage with new seals, or whatever is necessary, if possible. The leak appears to be from the rear portion of the center differential, but I haven't pinpointed the source yet. The DIYs I've found are more for front and rear differentials. Also, I can't seem to find any seals or gaskets (replacement parts) after looking briefly online. Any advice appreciated!

 

My mechanic used to order me all those specific seals through WorldPAC.

Sometimes its hard to find the parts anywhere else.

Goodluck though.

 

If you can't find the seal, go to the dealer. It's a pretty cheap part, and even at the dealer's prices it's not going to kill you.

I've done that before. Remove exhaust, remove the heat shield around there, remove drive shaft (but mark it so you get it back in the same position). Then there's a bolt that holds the output shaft in. Put a couple of the drive shaft bolts back in so you can hold the shaft and back out the bolt. The you just pull out the shaft and pry out the old seal.

 

on the 1.8 I don't think you need to remove the exhaust. It is called the Prop Seal which comes out of the back of the Center and to the drive shaft to the rear diff. you can remove the CV type joint behind the prop seal, move the drive shaft out of the way, remove the forward part of the CV via a bolt into the center diff, and then pry out the old seal and set the new one. I was lucky enough to have a neighbor with a seal driver of proper diameter. Not very difficult. But, I did this on a B6 (I have a B5, too).

 

Might be. I did it on a 2.8. I've never had the proper seal driver for any seal. Just use a big socket or a scrap of PVC pipe...anything round that's the same size.

 

Thanks guys! This is helpful. I'll see if I can get the part at the dealer before beginning the work, and I'll let you know how it goes!

 

Here is a DIY for an A8, but similar: audipages A8 Transmission Seal Replacement

I think this is the seal you're talking about. Not having to remove the exhaust would be a big bonus.

One of the drive shaft flange bolts on my B5 2.8 was seized, so be careful if that's the case on yours. I got my seal from the dealer and it was like $18 -- it's worth the extra money to know you have the correct seal before taking the car apart.

 

Nice DIY Redmond. That's pretty close to the A4 trans proceedure.

 

Thanks for the continued help guys. While searching for the part on Audi dealer sites, I came across the following website and diagram that was very helpful. Central differential, self- locking flange shaft for 5 speed automatic transm. 5 speed automatic transmission for 4 wheel drive 4.2ltr. rear rear 3.3ltr.. Fits: Audi | Jim Ellis Audi Parts I went to the WorldPAC site, but it looks like you have to own a shop to order things from there. Anyway, I'll let you know how everything goes, but it will likely be a few days before I actually get under the car and take a close look at what's going on. Thanks again!

 

I changed seal #31 to stop my leak.