The same process applies to the 8.8 rearend, only you have to add a LS(limited slip) additive to your gear oil.
1. A jack/jackstands will help you a lot. I didn't have one on hand, but still managed to get this done.
2. WEAR A SHIRT YOU DON'T CARE ABOUT GETTING DIRTY! This is a messy process.
1. A standard 3/8" drive ratchet.
2. 1/2" socket.
3. Brake cleaner.
4. Black RTV.
5. Flathead screwdriver.
6. 2 quarts of 80W-90 gear oil.
7. Oil pan.
8. Sanding block(optional).
Begin with placing your oil pan under your differential. Follow up by removing the fill hole plug with your 3/8" drive. If you have difficulty removing the plug, soak it with some PB blaster or WD40.
Next, you can start removing the bolts on your diff cover. Remove all of them completely EXCEPT the very top center one. Simply loosen this one.
The top bolt:
Once you have the bolts removed, take a rubber mallet with your flathead screwdriver and tap it between the differential and the cover.
Pry on it lightly (don't bend your diff cover!) until your gear oil starts draining.
Once the draining slows, you can remove the cover.
Your differential will continue to drip oil for the next couple hours, unbothered. If you don't have that kind of time, you can take your finger and scoop some oil out from the bottom.
Now, time to clean the inside of the cover!
This is where your brake cleaner will come in handy. Take a rag and wipe any excess oil off of the inside of the cover. Then spray your brake cleaner on it and wipe any leftover oil off. Clean off any residual sealant with a razorblade, more brake cleaner, and a sanding block if necessary. The sanding block will also ensure there will be proper adhesion from the RTV.
Do the same with the rim of the differential.
Next, you will put some RTV sealant on the rim of the diff cover. Apply it generously, going inside the bolt holes. Use your finger and make circular motions to spread the RTV around and rid any air bubbles.
Line up your bolt holes before placing your diff cover back on. You don't want to spread your RTV off the rim. Torque down the bolts in a "lugnut" pattern. Let your RTV harden, then fill up your differential and re-insert the fill plug. I almost used 2 complete quarts of oil. And you're set!
I coated the diff cover with gloss black spraypaint to make it look nice. Pics of it installed: