I swapped the 85 300D to a 240D 4-spd manual a few year back. Iam using the 240D FW and the 2:88 Differential. that is what I had available and what is available in any great numbers.
I finally found a 617 FW after looking for the past 4 years. If you keep checking the various PNP type junk yards, you will eventually find one. or keep checking the for sale forum, one might show up. PNP fw was $27.
NO not for sale.
The 240 FW will work "ok", but you will find some sort of vibrations most notably in 4th gear if you let the rpm`s drop to about 2900 on the HWY. usually around town you will be in 2nd and 3rd gear most of the time with the 2:88 Diff. I don`t get any vibs in 1st, 2nd and 3rd gear working up through the gears, everything is pretty smooth. as long as I keep 4th @ 3000 and higher rpm`s.
The 85 has been sitting for the past 18 months, (long story) but should be up and running by Fall with the 617 FW and a few other enhancements.
The car I got the 617 FW out of, was a 81 300D Euro, 617 NA, and probably the 3:46 Diff.
There is a guy locally with a Euro 300TD 4-spd that thinks it is gold plated. It`s full of junk, cover with tarps and rusting out. but won`t part with anything.
Charlie