Brett,
Reading your theory about “tweaking” the pinion nut, I’ve looked at the
pictures and offer the following [to be shot down in flames by those who know
what they’re talking about!].
If the taper roller pinion bearings are slightly worn and you did succeed in
tightening the pinion nut a few degrees to “take up the slack”, you would in
effect be moving the pinion towards out of mesh with the crown wheel.
This would be similar in effect to removing shims from between the inner [aft]
bearing cup and the casing thus altering the contact point of the pinion to
higher up the face of the crown wheel teeth and at the same time increasing
the backlash between crown wheel and pinion.
If this then proved to be excessive, you would have to add shims between the
back of the crown wheel and it’s inner bearing to move the crown wheel in to
closer mesh with the pinion [and remove the same thickness of shims from the
opposite side] - and you can’t do that in situ!
This in turn would alter the contact point of the pinion towards the heel
[outer] end of the teeth of the crown wheel.
So, Brett, I draw two conclusions from this theoretical exercise on a wet
Sunday afternoon :-
a) You would probably not get rid of the noise although you may perhaps change
the tune, and b) this is one thing you should probably not mess with!!!
As an alternative, perhaps you should give Hal a few crates of Moosehead
[whatever that is] after drinking sufficient of which he will surely do the
whole thing under warranty for you!
Good luck,
Bryan N
91 XJ 40 Sovereign [51K]
91 MX 5 / Miata [81K]
Cambs. England