I am sure someone will chime in with more knowledge than me but have you checked the ATF fluid level?

The problem is probably something else, but this would be where i would start to have a baseline.

I believe the procedure is close to this:
Car should be driven for 10 minutes or so to warm up the transmission fluid - not freeway driving
Park car on level service
Place transmission in Park
Check the dip stick near the battery/firewall - FSM recommends a bit of leather to wipe off dip stick
Fluid level should be at the top mark - very little fluid is needed to move the reading up so add a little at a time, while parked run the transmission through R, then D, back to R and then P and recheck fluid level. Repeat as necessary.



Chris

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1985 300D, 250k
1980 300SD, 180K