I have just recently purchased a 65 Unimog 404 that has the OM617 conversion done. I believe it has the aftermarket bell housing, without an access hole. I got it with a new clutch, but the through out bearing had fallen off off the shaft. I found someone to work on it, and he pulled the engine, reinstalled the clips and bolted it back up. There is some play in the shaft, and it fell right off again, so we are back to square one. Does anyone have experience with this? We are trying to figure out of the clutch fork shaft is supposed to be stationary, and would it be possible to create an inspection hole in the bell housing so that the engine wouldn't have to be pulled forward for access. Any help is GREATLY appreciated!