Originally Posted by cele0001
If anybody has an example of a hub where the splines do not engage fully other than bmw 6 speed transmission I would like to see it. As far as the misalignment theory I would like to say that perfect alignment does not exist. There is no 0.00000000000 match anywhere in the machine world. So, would it be possible to assume that tolerances for alignment were assumed for full spline engagement and due to lack of that engagement what should be " normal" misalignment becomes beginning of spline wear which is then positive feedback loop into destruction.
Agreed. My father-in-law worked 35 years as truck fleet mechanic, and saw a lot of clutch splines. When I described the R1150** clutch hub overhang to him and shared pics of various shredded transmission input shafts, he nodded grimly and confirmed that he'd never before seen splined mating clutch parts with such a flawed [my word] design.
The OE parts have/had some slop as new parts, according to local dealer service guys. Take that slop, multiply it by the hub overhang, apply whatever dynamic imbalance or parts misalignment might be present, and you get progressive pitting or spalling in the load zone defined by the wacky splined interface geometry. That's my theory.
So, tweaking the R1150 hub position to avoid most or all of the spline overhang seems like the smart move... Next winter I will do a spline inspection and install the tweaked clutch hub kit.
Btw, the old mechanic called BS on anything to do with spline lubrication, since many serviceable truck clutch hubs he worked on had little or no residual grease evident after long service periods.