Two questions for '87 300D tranny 261Kmi....
Ok, with this mileage yep, it'll clunk unloaded but, its not a concern worth attempting to repair without a overhaul.
As far as rolling back on incline, odds are the converter is worn and the working pressure is low due to age and mileage, there again, unless your overhauling I'd be inclined to let it be.
Your at or around the design limit mileage on these (not my words, MB tech training words) and more or less anything extra you get is gravy.
Personal opinion, drive it and enjoy the fact that unlike many of its 4 wheeled brothers, your Benz has one of the finest designed, longest lasting auto's out there. When it expires, overhaul it or replace it with a reman unit however be prepared for sticker shock on the converter pricing.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.