92 300D Transmission Issues

[Neuropel]

I have a clean '92 300D that has transmission issues. It has 153K miles and seems to have been well-cared for (I've put 20,000 on it). After letting it sit at an airport for a couple days while I was away on a trip, I'm finding I have to give it more throttle to get it to move (forward or reverse). Once moving, it shifts very soft, and it flares significantly on all shifts. I don't notice slipping once it's moving - just initiating movement and flaring between shifts. It doesn't want to shift into a lower gear properly on hills, and when it finally does it flares significantly. If I shift it manually on a hill, it's fine. I'm thinking it needs some kind of adjustment, but I can't find any info here on exactly what I need to check and how I would adjust it. It's not suffering rough shifts (which is what I found most commonly reported here when I tried searching). Transmission fluid and filter was changed less than 20,000 miles ago -the fluid and level both appear perfect. I'm really hoping someone can steer me in the right direction as I depend on this car for transportation. I know a fair bit about my siimple, old hobby cars, but I know very little about this diesel Mercedes.
Any help would be greatly appreciated.

[Wodnek]

You could be lucky, and it could be an issue with the modulator.

Double check that nothing got knocked off the linkage.