gqgifts

Hi,

I have a 97 E420 with 107K. The transmission was erratic....downshifting on its own, jumping gears, and slipping between 2 and 3. The TCU was completely filled with transmission fluid. I drained the transmission, installed a new seal at the harness, and cleaned the TCU and harness connections with contact fluid. There was no metal in the transmission pan. I reinstalled the TCU and now the car will not shift out of 1st gear. Any help is greatly appreciated. Thanks in advance.

gpniceville

Your TCU is most likely gone. I have dealt with that on several cars and always recommended checking quick disconnect at every oil change. I know that is all hind-sight, but I heard a rumor that dealership reprogramming is possible. Your car is in "limp home mode", second gear only. What you did in essence is allowed communications to begin again, but with a TCU buried in one inch of tranny fluid, there is no communications.

Best of luck

gqgifts

Thanks for the reply. After seeing how much fluid was in it, I assumed it was fried but wanted to give it a try. I'm going to the dealership today to have them remove the faults and we'll see how it runs. Thanks again.

1999E320

Where is the TCU located? Anyone has a photo of the location?
Thanks

gpniceville

Passenger side under hood against firewall. Big box with four screws. Open it and you will see several computers. TCU is usually smallest and black. It will not read TCU, but hard not to miss. If transmission fluid leaking, you will see residue on wires. Refrain from removing if there is a leak. Start with quick disconnect and replace if leaking has started.

1999E320

thanks for the info,is the quick disconnect located at the transmission or in the box with the computer
thanks

AMGfan

Transmission Fluid in ETC unit

The beginning of the story and the end of the story are night and day. Good luck.