My ’92 745 has the AW70L transmission with 200k. After replacing the kick down cable and changing the fluid a new problem developed. The torque converter won’t lock up. Prior to changing the fluid it worked fine. This is the second fluid change I’ve done on the car since I bought it with about 150k.

When driving around 50mph or above the rpm’s get pretty high.

50 mph – 2,200 rpm
60 mph – 2,600 rpm
70 mph – 3,000 rpm
80 mph – 3,400 rpm

Is it likely that during the fluid change debris got lodged somewhere to cause the torque converter problem and that doing a transmission fluid flush per the FAQ’s may resolve the problem? I’ve heard that flushing a transmission that didn’t have scheduled fluid changes (previous owners were neglectful) can lead to more problems. I’m concerned about causing a bigger problem that may render the transmission DOA.

I don’t know much about how transmissions work - any help/suggestions are greatly appreciated.

Michael
Melbourne, Fla

1985 740 460k
1988 780 Coupe V6 190k
1992 745 200k