Answer

I have websites that technicians write in around the country about problems with specific vehicles and a list of repeated failures. There were repeated internal transmission failures and external transmission control problems that which can be found usually by the transmission computer. If this computer sees an error, it will usually store a code to lead you in the right direction but still have to diagnose. First you have to find someone the the correct equipment to plug into the computer and look for codes. Most internal transmission problems usually don't set codes and require specific tool test the transmission before the transmission heeds to be replaced or rebuilt. Of course none of this equipment is cheap, especially for BMW. You could be losing hydraulic pressure for reverse, or damaged components. Transmission fluid is very vital for your car because it was really moves the car forward and backward. Most vehicles that I have in for no reverse end up going to the transmission to be rebuilt. I only trust one transmission in my area because that's all the do and they have been around as long as my shop has been around. Definately find a specialist who people trust. I completely understand your concern for keeping yourself from an expensive repair and thats why that 80-120 dollar diagnosis charge can finally give you the bottom line. I would hate to replace a transmission and not fix it because of something external that costs less then the transmission I just replaced for nothing. I hope this helps. If you have anymore questions, feel free to ask.

Expert:	Brian9
Pos. Feedback:	100.0 %
Accepts:
Answered:	2/3/2007

Automotive Technician

14 years automotive experience, ASE certified, Expert Technician in driveability.