I just did mine the other day. I use
synthetic Mobile I in the 75/90 wt. The "easy" way for me is to remove the fill plug, get some 1/2 inch plastic tubing from Home Depot or other, then with the passenger wheel off, raise the tubing up alongside the car, then squirt it in using the plastic bottles it comes in. It takes just under three quarts.
As for draining the old fluid, that can be a chore. Run the car until it is hot, then you can suction it out via the fill hole, getting most of it, or on my car, when my diff cover was off once, i had an AN 4 fitting welded in, so i can uncap it, and drain it out easily.
Just got back from the beach, came back in the rain, 220 miles, was down near Charleston for the Holiday. Cruised about 85, except when traffic was bogged down.
Pulled in for gas along the Interstate, this man wanted to take some pictures of my car, so I had him stand by it, and shot several with his digital camera. This sort of thing happens a lot with these cars.
all the best,