Hi there fellow E24 lovers,

I put up a post yesterday regarding the automatic transmission in my 1989 635csi highline. Having road tested the car this morning the problem seems to be intermittent. The automatic transmission warning light on the dash comes on and switches off again at random. Has this problem afflicted any of your 6ers? When the light goes off the automatic transmission works smoothly and changes up and down as it should do. Any suggestions please?

The fact that it works smoothly one minute and then quits and then back to working smoothly the next points to the problem being electrical rather then mechanical or in the hydraulic valving. Download the free PDF file of the ETM here:

http://wedophones.com/BMWManualsLead.htm

and go to 2460A-5 for a system description of how it works and then to page 2460A-0 for a system troubleshooting procedure. hopefully it is something as simple as a loose plug on the side of the transmission or at the transmission control unit or a dirty shift selector switch in the shift console, check these first. This might help finding the transmission plug:

http://bigcoupe.com/phpBB2/viewtopic.php?t=4746

Thank you for your time and suggestions which I will follow up.

yes, check the circular plug on the left side of the trans. it can get wet with ATF(trans fluid) or just dirty. if wet, clean with electrical spray. otherwise, just work the connector on and off a few times to clean off any bad contacts. there's about 7 pins in the connector. i repaired one of these trans that way. if it goes into fault mode, it is stuck in 3rd gear.

Thanks for your suggestion dm635, I'll check it out.

also in the glove compartment where the ecu is lies a plug that can work its way loose. I learned the hardway about that one. it has about 10 connections and is literally right in front of the ecu. I changed chips and somehow disturbed mine and when it disconnected my trans actted up.
goodluck