mainelyaudi

I'm sure I'm not the first as I've read some forums discussing this. I have an 04 A6 2.7 t. My daughter was on a trip and called toasay there was water on the passenger rear floor. The next day she called to say the car would start but not shift into gear. I had the car towed to a friends, and went up a week later to vacuum out the water and remove the computer so that I could order one (from e-bay). I put the new computer in, and car will not back up when warmed up. This is consistent with what I have read on the forums, requiring transmission work. I drive the car home. When home, I played a bit. When I installed the old computer, which was obviously faulty, the car would back up. With the computer removed, the car would also back up, even up onto ramps, and even when the car was warmed up. But with the new computer, the car would not back up. It would back up a few inches and then the transmission would slip. This would indicate to me that the transmission is not faulty.

Any feedback? What should I do. The car is in beautiful shape, but not worth the cost of what a dealer would charge to start replacing stuff.

Thanks, Derek
mainelyaudi

georgeb944

I doubt that the ebay computer was new.

Buy, beg, borrow or steal a full version of VCDS.

Scan the transmission control module. Check that the coding is correct.

My guess is that both of your TCMs are bad.

Prospeeder

So just unplug the ecu all together. Does the trans have forward 4th gear and reverse? If so, then I would try another transmission computer. If you try another one, and it still slips in reverse. What may have happened is, When the trans computer dies, and line pressure its not being controlled, the engagements into mechanical 4th and reverse is very very harsh. Some of these ZF transmissions have a known issue where the drum cracks and bleeds off hydraulic pressure, thus the slipping. When you have the working trans computer hooked up, its limiting line pressure much lower and is slipping. Unplugging it is increasing line pressure and not slipping. Yours may have been a weak drum and the limp mode reverse slam might have killed it. When the fluid gets hot, its much thinner and bleeds off much quicker. You need another transmission I would bet. Car-Part.com--Used Auto Parts Market I have had good luck with used units. Just keep it serviced.

mainelyaudi

Thanks for the response. The day my daughter could not get it in gear, she actually drove it about 150 miles until the car stopped with a bang in Bangor Maine. Without the computer hooked up, the car shifts smoothly into reverse and one forward gear, I can't tell cause the transmission lights don't work without the computer (TCM). This happens whether warm or cold. With the computer attached, when cold, the car will go into reverse smoothly, start slipping, then bang into reverse. When warm, the car only goes several inches before slipping, but won't engage reverse afterwards.