Difference between W115 transmission and W123 transmission

[w123fanman]

Well basically between the OM616/617 4-speed manual on the W115 vs the same on the W123. And also if you know about either, how much is the cost for each? I have a potential 4-speed manual out of a '82 240D that I would like to put in a 300D (still haven't decided between getting a W115 or W123) but don't know if it works or if I can actually use it (it's off my dad's 240D and he still may be attached to it though the car would need an overhaul (body is straight and all but needs new engine, paint and other things)