The ring gear is a press fit to the differential unit and must be heated slightly to allow it to expand enough to easily slide on. Heating should be done in hot water or an oven set at a warming temperature-never with a torch. Try using a torch, and you can develop hot spots and compromise the metal's integrity. Goldberg drives home the bolts that retain the ring gear to the Auburn Sure Grip differential unit. Remember, the bolts utilize a left-hand thread and should be tightened in a criss-cross pattern.