I had the same problem 5 weeks ago. Checked the fluid and it was darker than usual. So I changed fluid and filter. Reverse came back on. But two weeks later, Tranny can only run in first gear and locks-up going to second. Now it does not even move, but i still get my reverse. So I ask several shops about hte problem and the prices for a rebuilt is from 2600 dollars installed. I was going to buy a used one but still around 400 to 600 bucks. So I decided to rebuild it myself and when I opened the tranny and took out the C and D drive plates were gone and it melted onto the steel plates. I has to chisel them out. It cost me around 192 dollars for a rebuild kit . I just finished putting it together and I have a lot of extra o-rings that my tranny never had. I probably used ony about 6 o-rings and 6 snap metal rings. I'll keep you informed when I will test drive it This sunday.
How did your rebuild turn out? Was it hard to do, and did it work? I just bought a 735i with nothing but reverse, and I was thinking of doing the rebuild myself. Was the problem just the clutch plates?
