Hi,
I have a 2013 Suburban LTZ 1500 4WD and the rear pinion seal needs replacing. I just had the gear oil changed and now the pinion leaks. Go figure. Anyway, I can't seem to figure out which differential I have so I can get the proper seal. It's a 10 bolt cover with the fill plug at center right on the cover and it's got the tabs on the housing. I'm guessing it's an 8.5", but need to know for sure before I tear into it.
Thanks for any help.

10 bolt rear end

 

I'm pretty sure that would be an 8.265" sometimes shortened to 8.6". If you haven't already, read up on what to do when reinstalling with an existing crush sleeve. You have to mark things and count turns when removing so you can get the nut back to the exact same place as it was originally.

When I replaced the bearings in mine, I used the solid pinion spacer kit from Ratech.