03sl55amgmjd

I'm in need of some help to pinpoint a problem.
I was changing my TCU module on my 03 SL55 AMG and noticed some oily substance on the module and on some of the module pins.
I've never experienced any codes or shifting issues, yet, but would like to know where that oil could be coming from. Does anyone know if there are any oil lines, tees or fittings in the TCU mounting location that can be causing this oil to be getting in that area? Location is passenger footwell area behind the carpeting on far right-side under glovebox.
Thank you in advance for ideas.

cdk4219

I was under the impression that it wicks up from the transmission connector. There is an updated seal for the r connector that helps stop this supposedly.

03sl55amgmjd

Thanks for that info. I'll check into that tranny connector you had mentioned. Appreciate you responding.

latemodel21

As was indicated, you need to replace the transmission connector seal (also called "pilot bushing" by mercedes, why, who know) . The fluid "wicks" through the harness (to the TCU) when this seal assembly fails.
https://www.mbdirectparts.com/oem-pa...ing-2035400253

This part is less than $15 and should be replaced when you service the transmission (or every 50k miles).

It is easy enough to change (you will lose very little fluid when you take it out). Do make sure that you do NOT do it when the the car is warm (as you run the risk of spinning the captive nut that it is secured to).

As an added precaution on my 2003 sl55, I modified the mounting bracket for the TCU so that the connector is at the bottom (making it so if fluid ever reached the TCU, it would drain out around the connector rather than make its way onto the PCB)

HTH,
Chris

03sl55amgmjd

I appreciate the feedback from the forum members. I will be purchasing a tranny kit from FCP Euro and hopefully that will resolve my issue.