PackRat, I actually think that the job he has ahead of him is the easiest way to learn diff work. There is no pinion depth to change or shifting the carrier sideways required, heck he's not even pulling the bearings. As long as he keeps the main caps oriented properly (both left-right and up-down, I usually scribe L and R and add an arrow to point up), and remember which carrier shim goes on which side (there are only two from the factory, thickness is around 7mm each but they always add up to 14mm), he can reinstall the carrier exactly how the factory put it in. The only thing to really mess up is the pinion preload, but you really have to work hard to accomplish that - the kit I linked him to has very simple instructions, if you can add single-digit numbers you can install the kit. The one thing I wish the kit had was shim thickness marked on each shim, the way it comes you have to measure each shim and then remember which is which - still not hard, just mildly annoying.
Riot, my suggestion for the one-handed turning of the driveshaft was based that if you can accomplish that with all the drag on the brakes and inertia of the wheels, then your pinion is likely not self destructively preloaded. The OP said he uses a healthy IR impact tho, so I'm thinking he did go overboard some - really there is one way to find out, and at that point might as well do it right. And +1 on the RTV on the yoke splines, don't put it on the pinion cause then yoke will push it into the bearing - when you smear it on the yoke the pinion will push the excess RTV out towards the nut, which is where you want it anyways. And while a new nut is nice, red loctite on the threads of the old one will achieve the same effect. Plus with solid spacer that does not give and the high torque on the nut she really stands little chance of loosening even w/o loctite.
Laser, yeah, pretty much that's it - measure old sleeve and that's your starting point, then add shims if pinion turns too hard or remove shims if it's too loose. Actually the instructions with the kit say to start at .002 under crush sleeve thickness, either way is fine IMHO, worst case you'll have to shim it one more time, hardly a big deal. Btw how are you stacking your 8.8 posi: clutch-steel-steel-clutch-steel-steel-clutch, or clutch-steel-clutch-steel-clutch-steel-clutch? The factory rebuild kit comes with only 6 clutches, so if you wanna do the alternating pattern and run 8 clutches you'll have to either buy an aftermarket kit that has 8 clutches, or reuse the best 2 from your old packs. Also, be prepared to cuss at the S-spring, I can tell you from now she will not be very cooperative with you upon reassembly
Metal, get that sweating gears image out of your head, it's not what's going on in there. Gears still mesh fine, if anything maybe even slightly loosely now, they're definitely not jammed together. All that's happening is that your pinion bearings are working overtime, but if you avoid high speeds and try to limit your driving as much as possible I doubt there will be any damage done to them either. For your clunk near the transmission, check the u-joints, it's possible that till now the loose pinion was covering up a loose u-joint, but since pinion is no longer loose then you get to hear the u-joints instead.
