Re: [MBZ] '90 300D 2.5 transmission modulator adjustment

[Peter Frederick]

The control "box" is on the side of the IP, has three hoses on it and 
two screws in slots.  loosen screws, hold throttle wide open (engine 
off, since you don't want to toss a rod), rotate clockwise until you 
feel slight resistance.

If that doesn't fix it  you will need to adjust the modulator itself.
peter