So my E55 started slipping out of gear at all speeds and driving conditions, totally random... Sometimes 3 times or more on a drive to work. Had to shift it into neutral and then back to drive a few times for it to go back into gear. Fluid level is fine, ran codes and it said it needs a new Transmission Computer Control Module.

Has anyone ever experienced this before? Should I go ahead and get a used TCM since new ones are over $1200 and do a full trans service and see what happens? I was also wondering if maybe the troublesome pin connector having a small leak could cause a false code like this? That would be a much cheaper fix.

Also if anyone has an extra TCM part # 0335451432 I'll buy it off you.

Thanks for any help

 

What is the actual fault code? Used TCMs are plentiful and cheap (on ebay) and can be swapped without SCN coding (as long as it's the same model) but TCMs don't go bad all that often (it does happen, especially when they get fluid in them from a leaking pilot bushing, but it's certainly not the most common failure). Based on the symptoms, I would want to rule out a conductor plate issue before replacing the TCM.

Also, I believe you can swap a TCM from any year E55 (as long as it's a w211) even though the part numbers won't match. There are some differences, though: for example, the newer ones do not allow standing burn-outs for more than about a second.

A transmission service is probably a good idea for general maintenance, but don't expect it to fix this issue.

 

Have you had the radiator replaced? In 2003 they had issues with them contaminating the trans and ruining it. Probably not your issue, but could be something to think about.