ACE
I must admit I did not read all of your posted information. D o you have a printout from MB with any codes or adaptation data read out. If the transmission is slipping it can only mean one of two things, worn clutches as they said, verifiable by the transmission adaptation value data, Or a broken control pressure regulator valve spring, low working pressure; do you know if you have the updated valve body and conductor plate.

The o-rings on the transmission harness and sleeve are leaking, that is how transmission fluid reached the TCM. The fluid in the harness connector, transmission side; could be causing the solenoid codes.

The OBDII scanners and transmission codes are useless as a diagnostic tool, on a lot of models you can’t read the other modules that are linked thru the can bus, which is a must in diagnosing a drivability problem. In my case P0720 was a speed sensor problem, but no slippage in the transmission.


E420A1
There are only four codes that I know of, which would allow a key reset




Code


8 Reverse lockout solenoid
9 Starter lock out relay module, ETC control module output negative
51 engaged gear implausible or transmission slipping; this code will default to 3rd gear
52 command valve sticking in pressure position. One of three valves in the Valve body.


Do you know if your have the updated valve body and conductor plate. Does your transmission slip; it could also be a broken control pressure regulator valve spring if you have the early design VB.