HELLO I WANT TO SAY THANK YOU AGAIN FOR LAST RESPONSE. MY QUESTION THIS TIME IS THAT I WANT TO CHANGE THE FLUID IN MY REAR END. WHAT'S THE BEST WAY TO DO SO AND ALSO WHAT KIND OF FLUID DO I NEED. THANK YOU
The gear oil for the rear end is 80W-90 GL-5 (special lubrication for limited slip differential)
7 1/2 ring gears take 1.7 liters (3.5 pints)
8 1/2 ring gears take 2.0 liters (4.0 pints)
The best way to change the gear oil is to a jack up the rear of the car making sure that the proper vehicle supports are used and the front wheels are chocked so the car can't roll.
Remove all the cover bolts and let the fluid drain out. Clean out the metal filings the best you can and if there is a magnet on the rear cover clean that also. Scrap off the old gasket and install a new gasket when reinstalling the cover. Remove the 1/4 in square fill plug on the side of the differential and fill to the bottom of the hole. Replace the plug and road test the car.
I WANT TO SAY THANK YOU TO AUTOMOTIVE FORUMS. YOU GUYS ARE RIGHT ON. ITS HARD TO FIND SOMEONE WHO KNOWS ABOUT THE BUICK GRAND NATIONAL.