Lift the vehicle by inserting the jack under the housing of the rear differential. Once the vehicle is off the ground, position two jack stands under the axle and remove the floor jack.
Place a bucket or drain pan underneath the axle. Drain pans are wider and function better at preventing spills.
Remove the bottom bolts of the differential cover with the ratchet and 1/2-inch socket, and allow the fluid to begin draining the oil from the housing.
Remove the remaining bolts from the differential cover and place it off to the side. Examine the used gear oil and check for metal shavings. Examine the gear ring and pinion for damage and wear.
Clean the gasket with a shop cloth. The gasket is used between the differential cover and the housing. These gaskets are reusable, so be careful when removing the gasket and cleaning.
Reattach the gasket and the differential cover together and reattach them to the housing. Tighten the cover bolts down with the 1/2-inch socket and remove the fill plug in the cover with a ratchet.
Refill the differential housing with the appropriate gear fluid. 75-90W is typically used for larger rear-axle assemblies, and harsher conditions often require 75-140W, which can withstand higher heat.Gear oil lubricates and reduces heat in the differential of your vehicle. Dodge vehicles use differential oil to lubricate the gear ring and pinion inside the axle housing. The differential allows the wheels to spin freely through a series of gears and seals. Just like the transmission and other fluids in the vehicle, the differential fluid needs to be changed on a routine schedule. The intervals for changing the gear fluid are determined by the conditions in which you drive.