If you have any experience with this type of repair, I'd really appreciate your advice on whether this is a realistic DIY or if I should take it to a shop.

My 2000 A4 2.8 QTip is leaking oil in the area of the center diff. The oil collects on the small heat shield that covers the center diff and drips down right between the cats. It's done this for a month or so and it's getting worse, so I think I need to do something about it soon.

I can't see the exact spot of the leak due to the heat shield obstructing my view, but it seems to be either the seal between the center diff and the drive shaft or the center diff gasket. In either case, it looks like I'd need to drop the entire exhaust, then disconnect the drive shaft from the center diff before replacing leaking parts and reassembling.

So, would that be a complete PITA or can it be done as a DIY? Note that I have access to a lift, but not a lot of specialized tools. I did the belts and VCGs a few months ago, but for some reason this looks much more difficult, mostly because everything seems to hard to reach down there. Also, I don't see any DIY articles on this procedure.

Thanks for any feedback!

 

leaking engine oil- like from the rear main seal? or leaking trans fluid?

either way its not going to be fun. a lift makes the job much easier, there isnt any special tools you need other then a set of metric sockets and open ended wrenches, and probably some allen wrenches. its just going to be time consuming to get to where its coming from. get it up on the lift and find out exactly where the problem is first. take pictures if you cant tell what part it is.

 

Sounds like a rear main seal almost. I tried to do my rear diff seal and was scared off by the damn Bently book calling for all sorts of Vag tools for aligning the drive shaft and everything. Later was told it just looks scary and it's a DIY like ghost is saying. Double check to see what oil your losing first, if you can

 

Thanks for the replies so far!

The leak is definitely not engine oil. It's either trans fluid or gear oil from the center diff (separate fluids on the auto trans, according to the manual).

My problem so far is that the heat shield is obstructing my view and I cannot get it off with the tools I have because the exhaust is in the way. My thinking was to just get all the seals and gaskets for that area and replace them all after removing the exhaust.

I think with a u-joint and the right extensions I can get to the torx bolts and get it the heat shield off. I'll get it back on the lift this weekend and see if I can't do that and find out exactly where the leak is.

But has anyone ever removed their exhaust? The whole thing? That is the part that intimidates me the most.

 

exhaust is the easy part of the job, just pick a place to disconnect it, probably right after the cat converters (if that gives you enough room to get to the leak, or remove the cats too), and its only a handful of bolts after that. you might want to pick up some new bolts for the cat-to-downpipe connections because they sometimes get stuck or snap when removing them after all this time. and new gaskets for the cats. thats like $10 worth of parts and a dozen bolts and the exhaust comes off.

 

I guess I need to get it back up on the rack. When I looked at it last weekend I didn't see anywhere to disconnect the exhaust except about midway down between the cats and the front muffler. If there are other places to disconnect then I agree that the exhaust will not be an issue. I'll take some pics this weekend while I have it up. Thanks again for your input.

 

ya it's def the rear main seal, be careful replacing it, i've yet to hear a good story after some1 had theirs replaced. good luck man, hope it's not like that for you.