ZF10M transmission explosive shifting.
I am re-posting my question from 10 months ago, with some further notes. Except for some sympathy, there was not much in the replies.
Anyone knows of this or can recommend an expert? I have bought used ZF10M from a fisherman in Alaska
, with some verbal assurance that it was OK, but no guarantee. Took a calculated chance. Figured that worst case, I will rebuild
it. The original was Hurth HBW50 (on a '82 Universal M25 diesel) and it lately suffered from the here oft debated problem of not going into forward. Now, half year later, the 1" longer ZF10M is finally installed and it goes in forward and reverse, but it does so with what seems like unnecessary gusto. The klonk is very loud and to my mechanic's ear it sounds like it won't be long before something breaks.
I have installed new damper plate, the idle is low, where it's supposed to be and there is a PIY flex coupler. On the bench, it seemed to turn smoothly, no play in either shaft, but a little too tight for a well used transmission, as if the bearings were in some pre-load. The previous transmission, from brand new, made much more reasonable klonk when engaged. (Of late, no klonk at all)
I wonder if someone has rebuilt the transmission and did not adjust some clearances properly. I have, 23 years ago (it worked well until few years back) rebuilt the Hurth because of water
intrusion and remember the shims, the calculations and the mysterious clutch
engagement assemblies. Could the type of ATF used make a difference? (Now I am clutching at straws).
Any ideas? Thanks, Stan.
PS I forgot to bring up work
I have done on a boat
with a larger Hurth gearbox
4-108) where the shaft actually came out of the flange after destroying itself, the key and the flange. The owner did not mention and problems with the transmission, but when we installed new shaft, flange, damper plate and flexible coupler, the gearbox
shifted with similar loud clonk. The idle RPM
was rather high and after fixing a sticky linkage and lowering the idle, the clonk became tolerable to my ear.
Since then, I observed another ZF-10 transmission with a loud shifting. Can it be the nature of the beast? Again, my old Hurth 50 worked well for thirty years, twenty after a rebuild, with a sound about like when you shift a motorcycle into first gear