How To Change Rear Differential Fluid

I need to change the rear differential fluid in a 2001 AWD Safari. I assume that I need to remove the rear differential cover in order to drain out the old fluid. Can I reuse the existing gasket or do I need to install a new one? Do I need to add anything other than the 75W90 gear lube? Any other information anyone can supply regarding this matter will be greatly appreciated.

not sure how they are on the safari, but if you havent looked yet, go check it out, there usually is a drain plug at the bottom and another plug where you fill at, on level ground, pump fluid in until it starts to run out and then plug it up.

I don't think there's a drain plug. Some shops use a pump to get it out, but for the home mechanic taking the diff cover off and replacing the gasket is the way to go. You can also invest in a nice shiny $20 ebay chrome diff cover while you're at it.

oh, sorry, never worked on one that hadnt had a drain plug yet.

oh, sorry, never worked on one that hadnt had a drain plug yet.
Better late than never....Yes you need a new gasket after removing the cover. You also need a GM diff additive that is available at the same place you will buy your 2.5 liters of oil. Fill plug takes a 3/8 drive extension to remove and is on the right side of the diff just above the axel tube. Put additive in first then fill with oil until it starts spilling out of the fill hole.