mncollege

My 1997 A8 4.2L Quatro thumps going from 2nd to 3rd and 3rd to 4th and 4th to 5th. Had a so called expert diagnose and could not determine the problem; says his diagnostics could only take him so far! I can shift smoothly in all gears manually but I sure hope I won't have to indefinitely. Car has 115,000 miles and I enjoy it otherwise. Also, consulted with a tranny rebuilder who believes torque converter is not the problem. I need informed suggestions on continuing diagnostics or definitive solution(s) thanks in advance.

JimTheBarber

According to the expert on this forum, TozoM8, the issue is the way the valve body and/or the throttle position sensor interact. He sells a modified valve body and TPS that is supposed to solve the problem. There is the possibility that replacing the filter and/or filter and trans fluid will help or fix the issue.

PaulW

Can't really tell from the description of the problem.

JimR

I added a can of red Lubegard transmission additive with a fluid/filter change, which I believe gave me another 10-12,000 miles before I had to do the transmission rebuild.

TOMAS7

Check out www.audipages.com for tranny service.

mncollege

Tranny fluid and filter changed at 90,000. Currently have 115,000.

tozoM8

^^^ That's what I would do. It is going, but lubeguard could buy you some time.

mncollege

Follow up to 1-29-08 posting. Still searching for the culprit causing the thumping and gear searching. Its suggested that the "throttle position sensor" may be the guilty part! Can anone tell me if they had this malfunction and what were the syptoms? Would appreciate your help--don't want to rebuild entire tranny just yet. Thanks again.