OM605 with cdi gearbox
OM605 with cdi gearbox
As far as I know all Mercedes 5 speeds are quite weak. The 3rd gear breaks first. 717.460 from C250TD should be a bit stronger, maybe it could handle 300hp. You can swap the tail housing for one with a mechanical speedo drive from an older gearbox.
717.404 dog leg (first gear left and backwards) five speed from the 190E 2.3 - 16V is much stronger than Mercedes gearboxes, but it only has 1:1 5th gear . 717.450 is the same gearbox but with short input shaft for dual mass flywheel, it was fitted to the 300E - 24V