Originally posted by Mike Richards
The Mercedes Benz Maintenance Manual 1981-1993, service task 2702 - Automatic Transmission fluid and filter change - clearly indicates that the fluid is drained from both the converter and the main pan. The filter in the main pan is also changed along with the main pan gasket. Drain plug washers on both main pan drain plug and converter drain plug should also be changed.
Go back to your dealer and have him review the contents of service task 2702 with you.
For pre 1989 models ATF change are indicated at the 30k miles service, always including converter, gaskets and filter. I personally change it every 15k.
A simple wiring device with a push switch connected to the poles of the starter (after disconnecting the pole to ignition) allows you from under the car to cranck the engine bit by bit until the converter allen bolt lines up, saving the hasle of cowl, fan and trips back and forth to check the allen bolt!.