mattgt5

OK, putting ARB Diff covers on this weekend and I have had 18 million different answers from people on diff fluid. Advanced auto says that both diffs take 80W-90 Gear oil. Do I use that, or do I use the 75W-90 synthetic. How much in each. Advanced computer pulled up 2.7 PINTS for front and 4.75 PINTS in rear, but then the guy said to just fill it to the fill hole. NR 4x4 told me two quarts each. The ARB instructions say to lay the cover beside the oem cover and tape a line from the fill hole of the oem cover over to the dipstick on the ARB and mark a line, fill to line. Which is correct? can they be over-filled? Thanks for the feedback

ronjenx

80W-90, 75W-90, makes no difference.

Use the published quantities as a guide to how much to buy.

Fill to a little above the level of the bottom of the axle tube. This will allow the oil to flow out to the axle bearings in the rear axle, and will flood the carrier bearings in the front axle.

Here is a picture showing the fluid level as it relates to the bottom of the axle tube.

Your new cover's fill hole is probably higher than the stock cover's fill hole, so look at the oil level line in the picture as compared to the axle tube.

mattgt5

Thank you. That is very helpful and lines up with the instructions on the ARB covers.