99.5 A4 1.8T - Vehicle won't go into reverse.
The passenger side was flooded during the severe rain we experienced on the East Coast last month. I initially experienced the classic symptoms of a flooded TCU. The instrument panel PRDN21 displayed a rectangular block outline which I guess is consistent with a TCU in limp-mode. I ended up running a de-humidifier inside the car for 3 days to dry everything out. I then replaced the TCU with one that I purchased from a salvage yard. Everything was working ok for about a week. Then my reverse stopped working. At first, it would engage when the vehicle had been at rest for a few hours, and now it doesn't seem to work at all. I have to push my car (in neutral) out of every parking spot now.
Someone on the forums posted something about an F-seal failure. What's the solution to this problem?? I'm really praying that I'm not looking at having to replace the transmission.

 

are you standard or auto. if you standard then it might be the syncros if you auto then its time to get a new tranny becuase your tip probably went out. we have a a6 in our shop that lots its reverse and it needs a rebuild

 

Did you put in the new TCU?? Were you extra careful not to bend or break any of the pins off the bottom?? Did you inspect it to make sure it was physicaly in good shape before you bought it/put it in?? Have you tried cleaning any obvious electrical connections/points on the outside of the tranny like wiring harness's etc?? Ty replacing the fluid/filter as a last resort, but i dont think that would have anything to do with it.

 

I have an automatic. Please tell me I don't to replace my tranny! This really sucks...

 

Yes, I put in the TCU. I was very careful with the connector pins. The TCU was in perfect condition before I installed it. I did not try cleaning any electrical connection points on the outside of the tranny. Do you have a Bentley screenshot you could send me? I have not tried replacing the fluid/filter because of the difficulty involved in performing that service. I really should have paid someone to do it a while ago.

 

I would just get under there and take a peek with electrical contact cleaner and a small wire brush in hand. Disconnect the battery before you do this... Im not familiar with the bottom of the tip tranny or what/where wiring harness's are, but if there are some conncected to it i would unplug them and spray just a little cleaner in there. Just dont use too much. If that doesnt work you may want to go back into the tcu and use some elec. contact cleaner on it as well where ever you can. It could be something stupid and as simple as removing the tcu and just reinstalling it. that would be a fluke, but stranger things have happend. If that doesnt work, change the fluid and filter, if that doesnt work, its probably rebuild time. Auto tranny's are scary.