Your rig’s differential cover is like a target just waiting for the first boulder on the trail to hit a bull’s eye. One hard whack from Mother Nature is enough to take even the burliest rig out of commission. It’s a good thing there are plenty of performance rear diff covers that absorb serious punishment. Even though they’re tough, they still leak like a sieve if installed incorrectly. So, make sure your rig’s differential doesn’t run dry by following these easy steps.
Provide the Perfect Platform & Good Seal
Diff covers range in construction from stamped steel, cast aluminum or cast-iron pieces, depending on your ride. But regardless of the material, they all require a smooth mounting surface for a leak-free fit. After you remove your ride’s differential cover, gently clean the mounting surfaces of both the differential cover and the differential carrier. Also, avoid using heavy scraping tools like chisels or flat-head screwdrivers to clean surfaces as they damage sealing surfaces.
If you grabbed a solid diff cover for your rig, slapping a value gasket under it is just asking for trouble. Those cheap gaskets are too thin to fill in uneven surfaces and often degrade over time. The result is a pool of expensive, gear oil under your rig. Your best bet to prevent leaks is using a heavy-duty gasket or sealant that’s approved for use with gear oil.
Gradually Tighten the Cover
The goal is to gradually seat the cover evenly on the gasket and differential carrier. This is where extra patience pays off. If done properly, this prevents the gasket from shifting and keeps the cover from warping, or in the case of an aluminum diff cover, breaking. Start by ensuring your hardware is clean and consider using thread locking compound on each bolt. Next, screw each bolt in by hand and in a star pattern, just like you’re installing lug nuts on your rig’s wheels. Once tightened with your fingertips, put a socket on each bolt and tighten again by hand. At this point, you’re ready to grab the right tool to finish the job—a torque wrench. Torque specifications vary depending on the material and grade of fastener, and the material of the diff cover itself. Follow the instructions that came with your cover, they will usually fall between 20-30 ft/lbs. ARB for example, recommends right around 25 ft/lbs for most applications.
Hit the Road
Installing your rig’s differential cover correctly allows you to enjoy the highways and trails, knowing that at least one part of your rig won’t leak its vital fluid. Beyond bolting on differential covers, this guide demonstrates how a careful and thorough approach to modding your rig pays off. So, remember the importance of the little things, like surface preparation, gasket quality or bolt tightness and enjoy your rig’s mods a lot more.