the crush sleeve is what spaces between the 2 pinion bearings, that and the tightness of the nut maintain correct pre-load on the bearings

Its critically important this be maintained within specs or the bearings will fail prematurely

therefore, if the seal is changed out, first mark with a punch the nut relative to shaft, then count turns to undo

tighten back up so punch marks align precisely

in theory, pre-load should sta same as before.

I use a small slide hammer with self tapper, drill a small hole, to pull pinion seals, its in there dang tight

 

I got the feeling this will fix my rattle....

 

I was thinking to put on a new tcase-shaft seal while I'm here, as I saw that I was running a bit low in tcase fluid.... Apart from pinion seal and maybe tcase-shaft seal, would you suggest to put new bearings in? I see they come for rather cheap... are they worth/easy to replace while I have the pinion seal out? what about new crush bearings?

 

no. to change those, you gotta pull the pinion out, then you definitely will have to do a gear setup.
yeah, now would be a good time to replace the transfer case output seal also. it's very easy to change. much easier than the pinion seal. but very similar in theory.

you don't want to change the pinion bearings as you will need to pull the pinion out to do it, resulting in a new crush sleeve and ultimately having to do a total gear setup. this is quite costly.

i would just change out the seal and hope for the best. when turning the nut back on to the punch mark (as stated above), i would then use a needle type torque wrench and go about 5ft lbs more. not much, but just enough to lock the nut back tight. this shouldn't crush the sleeve much more to mess up your gear meshing/backlash. also, use blue loc-tite here.

cheers.

 

All good then, just purchased my new seals (and while I was there a cheap tailpipe and muffler) will keep you posted on how it turns out.... As threadstopper I see that many people over here use few straight drops of loc-tite superglue... I'm tempted to give it a shot as I rememebr using it to lock the threads of my vespa cylinder head ages ago .... It held on for a good 6-7 years with all that heat...