StanA8L

I have a 2001 A8L with 125,000 miles. I believe trans oil and filter were replaced at about 75,000?

When stopping the car from any driving speed over 35MPH, a shudder develops at about 15-20MPH. I think it is the 3-2 downshift? Or, it feels like the torque converter is locked and has not disengaged.

If I very slowly brake, the downshift occurs without a shudder.

I don't think it's the brakes as it only happens in the narrow speed window around 15MPH. I can't feel if the shudder is in the front or rear? Just feel it in my seat.

Wondering if it could be axles?

Afraid to ask the local Audi dealer.

Thanks for any help!

silverd2

Very unlikely that it is an axle issue...not a typical symptom.

I have no diagnosis, but can suggest a couple of things to help develop one:

During symptom (shutter), pay close attention to rpms...what happens? ...is it a downshift (rpms rise suddenly) at the time of the "shutter"?

Try coming to a stop at the same "problem" rate with trans in neutral, to see if same symptom occurs.

StanA8L

Thank you silverd2!

I have tried it in neutral, and don't get the same shudder, but I get a slight clunk upon reaching a stop. I have also tried it in tiptronic, both manually downshifting and letting the car downshift itself. No shudder on manual downshift, though I think I downshift too early to beat the computer from doing it. The shudder seems lessened in tip mode but is still there depending on how hard I brake.

I am uncertain how the torque converter works. But it appears to lock-up after shifting into 3rd gear? I had a car that the torque converter had premanently locked and wouldn't release. The shudder seems similar, though in my old car, it shuddered all the way to a stop.

I have not checked the RPM's and will do so and report back.

Thanks again for your help!

StanA8L

I watched the tach has I was breaking, and from say 35MPH, the tach smoothly decreases, at the shudder, the tach bobbles. When the downshift happens, the RPM's blip up a little then continues down to idle with the stop.

In tip mode, letting auto downshifts, the downshifts seems to happen at different speeds, so the shudder is minimal. No shudder in neutral.

I had a GM product that torque converter wouldn't release. It would act like a manual coming to a stop sometimes killing other times would shudder until TC released. GM products release TC when the brake is used. Could that be the issue?

tozoM8

I would put a bottle of red lubegard in it to free up the valves in the valve body.
http://autoparts.findyourauto.net/LU...029548321.aspx

StanA8L

Thank you! Will try the lubeguard and report back.