Mercedes Benz repair: MB300E Transmission, proper diagnosis, sensor wires

Question
After about 20 minutes of running, the transmission will slip back into second gear. I can goose the gas pedal and sometimes it will go back into drive only to slip out again when you get off the gas. I am now having a problem with it not shifting out of first. HELP!
Bobby

Answer
What year?
How many miles on the car?

Possible answer:
Limp mode = MB dealer.
Internal mechanical issue = MB dealer.
Seal leak soaking sensor/wires in oil.

The least cost for this diagnosis, should be your local MB dealer, a proper diagnosis will save you big $$$$$.