I have a 1999 Mercedes C280
I purchased the car well traded not knowing much about it but it is and was a huge step up. Same day I got it the battery died I left lights on for a few, jumped it to get going again. A week later had transmission fault codes and tranny felt like it was slipping wouldn't drive after it got hot.....
I have since replaced the TCM, The Entire Valve Body, The Plug, - Each 3 Times and recently the wire harness from the tranny to the tcm.... I managed to get the car running anywhere from 3 days to 3-4 weeks longest this last time... But after an hour in traffic suddenly the tranny went again
I got codes
0753 - Shift Solonoid "A" Electrical
0758 - Shift Solonoid "B" Electrical
0763 - Shift Solonoid "C" Electrical
0745 - Torque Converter Clutch Circuit Electrical
0715 - Input/Turbine Speed Sensor "A" Electrical

I have replaced All common problems but when I replace TCM all is well and intermittently it goes out I can't tie it to anything specific most of the time I need to be driving for a while for it to happen. I strongly feel its electrical, A relay, bad ground.... I don't know how to test for this...... With that said I have an unrelated error code P0410 I believe it's for the secondary Air Pump... but whenever I fixed the transmission and this code would also intermittently pop up but easily clear out causing no issues.......
I need transmission Help I'm at a loss I never had fluid on the plug or in the TCM I don't know what's wrong please help!!!!!
I had the car at an independent shop at one time we thought we had it fixed this last time it lasted 2-3 weeks ran and drove like a dream and after a good hour and half of driving the transmission code P0700 popped up then the other codes came after I tried to clear them - What is causing the TCM to trip out????

Do you get the same batch of codes every time the trans goes into limp mode?

When you replaced the valve body, did you change the conductor plate?

Did you ohm out the solenoids?