Picking up again on the meshing between the axle shaft gears and pinion gears when the Gov Lock mechanism applies pressure to the clutch packs.
Axle shaft gears = side gears, splined to the axle shafts
Spider gears = pinion gears
The mesh is sloppy to begin with. I have believed for years that some of these side gears/pinion gears are not even machined--they're forged (perhaps from powdered metal--near-net-shape) with only the most rudimentary geometry to the gear teeth. But I don't know that for sure.
With new-ish (fairly tight) clutch packs on both sides, the overall movement wouldn't need to be very much. As the clutches wear, the movement of the ramps on the one side gear and the ramps on the mating piece would travel farther, increasing the separation between them. So some of the additional travel would be used to lock the left-side clutch pack, with the rest being used to lock the right-side clutch pack.
As the right-side clutch pack requires more movement to compress the worn clutches, the side-gear travel would increase. But as I said--side gear mesh with pinion gear mesh is pretty sloppy.
Would (outward) axial motion of the pinion gears on the pinion shaft be part of the mechanism for allowing the gap between the axle shaft gears (when clutches are activated) to close without 'pinching' the pinion gears?
I noticed on mine, with trans in park and one wheel stationary, rocking the other wheel back and forth within the available motion (backlash), one of the pinion gears (I didn't notice what the other one was doing, only the uppermost one) would rise and fall on the pinion cross shaft as it turned back and forth.
The GM manual (page 4-178) describes a process of 'adjustment' where (with the thrust block removed) the axle gear (on the ring gear side) is forced away from the pinion cross shaft and the (rotational) backlash of the pinion gear is measured (with a dial gauge) and 'spec' is achieved by changing to thinner or thicker thrust washers behind the axle gear. This is then repeated for the other pinion gear. At no point is the passenger side (my troublesome side) axle gear involved in this procedure.
Apart from not having a dial gauge mount at hand and, at that point I believed I'd substantially reduced the axle shaft end float, I never pursued checking this but it would seem that a thicker thrust washer behind the axle gear would reduce the backlash between the two gears in question - but not necessarily reduce the axial motion of the pinion gear on the pinion shaft - merely 'fix' it in a more outwardly position (preventing it from moving inwards). Given that outwards is OK, any thoughts of a shim on the outside of it (between it and the carrier) are misplaced - my initial though.
Should I be concerned that the pinion(s) have such freedom of movement (recap - the positions of the axle gears in no way endangers displacement of the C-clips) and merely accept that my diff will be touch 'clunkier' than it could be (all diffs are clunky to some extent - no?).
Or, with the trans in park (zero prop shaft rotation) and one wheel static, is there an accepted (in degrees of) rotation CW and ACW of the other wheel which would possibly ascertain if my diff is out of spec?
Two more observations.
My spring (cam plate side) appears to be functioning. It can be accessed via holes in the carrier and when I push inwards there is movement then a return to position when I quit pushing.
The GM manual suggests fitting a thinner side gear thrust washer if the side (axle) gear cannot be pushed inwards enough to permit installation of the pinion cross shaft. Not necessary in my case - but occasional resistance was felt when seating the shaft.
And finally, if I have to fit a thicker thrust washer, is this possible with the carrier in situ (in axle case) or does it have to come out and the Gov Lock mechanism be dismantled for access?
