QUESTION: Is 12thou end float on a diff's output shaft too much?
I've just finished rebuilding my gearbox, then turned my attention to the diff as I noticed there was too much play in the output shafts for my liking. Play was sideways wobble on the cage-side output shaft, and in/out float on both output shafts. This is a MiniSpares X-Pin diff that I fitted new 17k miles ago. Sideways wobble will be cured by new bush in the end of the cage (and half an hour in the machine shop), but I'm having problems eliminating the in/out float...
I've replaced the mica washers with the thicker BTA102 variant (measured at 41thou, compared to the 35thou of the old ones I removed). That solved the issue at the crown wheel end, but I still had a good 12thou of in/out float at the cage-end output shaft. Since then I've also fitted new planets, planet bushes, and output shafts. No change... still 12thou of float.
I'm at a loss to understand where that extra/unwanted float is coming from.
The only things I haven't changed are the X-Pins/block, and the cage itself. There isn't any noticeable wear on the thrust face of the diff cage (you'd be able to see/feel 12thou of wear very easily), and likewise there's no wear on pin surfaces where the planets run (pins measure 0.563" along their full length).
Any suggestions of what I should try next?
Adding 10thou to the mica shims (if that were even possible) runs the risk of the output shaft hitting/binding the X-pin center block. My only thought is I need thicker planet thrusts (which aren't available?)... or to fab up additional planet shims (from 10thou bronze sheet) and slip them between the cage and the current planet thrusts... but that seems like putting a bandaid on a problem rather than underfunding/addressing the root cause. And the really frustrating thing is this diff was tight as a gnat's chuff when I fitted it 17k miles ago!
... or am I missing something really obvious?
Edited by colinu, 08 February 2019 - 06:30 AM.