JSAudi100

The ol' 100 is up to no good. Yesterday I was driving down I-81 to Christiansburg, VA. I stopped for gas and proceeded to check the oil. When i opened the hood, smoke was floating from the rear of the engine compartment. It stopped, I crawled under the car to see brownish colored fluid splattered across the underside of the car, and drops of fluid on the final drive housing. I am guessing that one of the seals between the trans. and the final drive has given way. Does anybody have any input as to how hard this is to repair, estimated costs, and could it be something else? The transmission was rebuilt approx. 20K ago.

DanA100

Make sure your transmission is not OVERfilled with AT fluid! I had exactly the same problem with the same car, less than 20k miles after AT rebuilt. At the begining it didn't leak, then it started to do it. *** It was overfilled and when driven for long time and when hot it was leaking from the two black caps/vents (mashroom looking) on top of the tranny/final drive. You can see these caps from under the hood, they are deep right behind the engine. Use a flash light and check if it is WET around these black vents/caps. My guess is that it is very wet and it is dripping on your exhaust.
Also, Check the level of the tranny fluid when the car is hot(after 5+ miles drive).
If too much fluid, take it to Audi mechanic for fluid level adjustment ASAP. Bring the level to almost "Min" line.
BEST thing to do, since it has over 20k miles already - drain old fluid, put fresh AT fluid and double check the level. Keep it close to "min" but not below.
Good luck!

audijim113

my 86 has been doing the same thing for 4-5 years. basically it was a common problem for the final drive and auto tranny to "swap spits" gear oil would get into tranny and tranny fluid into final drive. gear oil won't hurt the tranny, but the thinner trans fluid won't lube the gears sufficiently.

my fix has been to crawl under there once a year and suck out the final drive fluid and replace with new. it's a pain in the ***, but sure beats the cost of a new tranny/rear seal job, which would be upwards of $1,000. even if you had a dealer suck it out and replace fluid, it would take a lot of fluid changes to exceed the thousand bucks.

DanA100

How much final drive oil do you suck out and how much fresh do you put? What is the capacity?
What kind of final drive fluid are you using?

JSAudi100

Thanks for the input. I dropped the car off at my mechanic's shop yesterday for a transmission service. He said he'd check it over. I hope you're right, i hate the thought of rebuilding again.