The pinion gear is in way too deep and digging into the ring gear carrier. The pinion gear must have slipped in when you had it apart, and the inner bearing wasn't seated back in place when you reassembled. And, the ring gear teeth are getting shaved down like a knife edge. It's toast.

 

See in the pictures? The line going across the carrier? Is that the carrier broken in half? Or is that line suppose to be there? I dont remember when I took the cover off to change the seal if it supposed to be like that. Also, the pinion nut didnt have any threads exposed past the nut meaning it is almost at its maximum looseness. And I talked to my mechanic and told him the tightness I put it, and he said that should be way too loose, he said it always zips it on with impact gun till it stops and never bad a problem. So I dont know I'm being told like 4 different torques. Time to take it to a shop...

 

I pretty sure none of those parts are savable. Its going to be very pricey.

Here is what I think happened.
There was a misunderstanding on the 24in/lbs. That is the torque resistance or pre-load on the pinion bearing is suppose have after the the crush sleeve is crushed not the pinion bolt torque. The confusion is because there is no torque spec for re-tightening the pinion bolt because GM says not to do that. GM says crush a new sleeve. You torque your pinion nut to 24 inch/lbs which is no where near tight enough. it could have even been stopped by a small amount of dirt. The pinion was so loose that it just pushed away from the ring gear instead of driving it. When it pushed it way it drove it into the carrier.

None of this really matters. The milk is spilled.

I would guess the repair will cost 600ish with used parts closer to $1300 with new parts.
Or you go to a junk yard and buy a complete rear axle for $350 and install it yourself.

The process to crush the sleeve is a pain.. You assemble everything and you can tighten with a air hammer. Then with the rear dif out you use a torque wrench to check how hard it is to rotate the nut/pinion. This is where it gets fun, You keep tightening the pinion until it take 24 inch lbs of force to rotate the pinion. Yes I have seen grown men hanging on extensions trying to get to specs. I have even seen mechanics use their lift and the weight of the car to get the crush sleeve to crush.

 

Which is why I suggested he ditch the crush sleeve and go with a solid pinion spacer if he decides to put new stuff in. No hanging off breaker bars, no worrying about crushing too far and so much less time consuming.

Gotta say, never seen a rear do that. But I guess when I think about it, I always tightened with an impact and then checked rotational torque.

 

Yeah guess it was too loose so pinion just went in and kissed the carrier....R.I.P

 

I'm pretty sure I have a spare carrier and gears...but they are 2.73 so unless you really want great fuel mileage on long trips they are probably not worth it for you. Hahaha

 

lol thanks anyways, what do i need to buy if im restarting from scratch? Carrier, pinion+ring gear, bearing kit, shim kit?

 

You are going to probably need the spider gears also. Not sure if they make complete bearing kit You need pinion, carrier and wheel bearings.