I just got done performing a rear differential service on my 08 SUT recently purchased and wanted to share some details. Many will say you must replace the original differential cover bolts or you risk the problem when re-installing them an having them break. Considering I have completed this service on my 05,06 and now the 08 I can tell you this is not necessary, simply clean the removed bolts well with a wire brush to remove ALL the locktite the factory used when originally installing them then use blue locktite (along with the factory re-useable gasket),
refill with a good quality 70w90 synthetic and your good to go. I like to remove the cover just because pulling the plug on the bottom will simply drain the old fluid and not remove the crap that settles in the bottom of the housing. Here is some pics of the final service pictures, I also cleaned up everything, replaced the stabilizer bushings and performed a general cleanup. She is ready for another 100k.

 

Nice work and very clean looking under there, Thanks for sharing, I too wouldn't replace the bolts just clean and seal well.

 

Thanks for the compliment, she has never seen snow or salt and now rust so it was really clean to start with and made it easy. Now its off to the front end, upper control arms have torn boots and need replacement. Cheers