Worst trans I ever worked on (discounting auto trans) was an Austin Healey 4 speed (non-synchro 1st gear) with the over drive unit hanging on the back. That was HELL!!
Counter shaft was near impossible to put in but the worst part was getting the splines to line up to accept the "slip in's place" rear OD unit. Took me two days to "slip it in place", dang near gave up, freakin' nightmare. I'll never touch another one.
