1990 535i: Transmission does not reverse!

The automatic transmission of my 1990 535i stays still when put in reverse mode. This happen after I left the car with a mechanic to change a hose. All the forward gears change very well.
When I checked the oil level of the tranny, it was overfilled -- not by me. Could there be some "bands" that need adjusting or do I really have to rebuilt or replace the transmission?

How can you check your tranny level when it is a sealed system?

There is a dipstick for that transmission. Just warm up the car and let it idle, take the dipstick it out, wipe it clean and put it back. Then remove it in order to measure the fluid level.

I must have been too nervous to pull hard enough on it to take it out.

Thanks, lets hope it's at full level. I just did a 10,000 km road trip. :D

Try getting it back to the normal oil level, and see if it will shift then.

BTW there are "bands" in an automatic tranny, although I don't know if they are adjustable. Also valves that open and close due to pressure from the tranny fluid. I won't even try to explain...because honestly I only thought there were valves and tranny fluid.

Here's a nice link:

http://auto.howstuffworks.com/automatic-transmission4.htm