How to Install an Aftermarket Differential Cover

Step-by-Step Guide: Installing an aFe Rear Diff Cover on Jeep Wrangler JL

In this guide, we’ll walk you through removing your factory differential cover, draining the fluid, and installing an aftermarket replacement. We’ll be demonstrating the process using an aFe POWER rear differential cover on a 2020 Jeep Wrangler Unlimited JL. Whether you’re working with a lift or using a jack and stands in your garage, this DIY upgrade offers added protection, improved cooling, and easier maintenance for your axle.

Step 1: Drain the Rear Differential

Position a drain pan beneath the differential. Remove all the bolts except the top one to hold the cover in place. Tap the cover with a hammer to break the seal—this will allow the oil to begin draining. Let it fully drain; this can take up to an hour depending on the oil’s viscosity.

Pro Tip: Do NOT spray brake cleaner inside the differential. If you do, you’ll need to fully flush it out.

Step 2: Remove and Inspect the Gasket

Carefully remove the factory cover and take the reusable gasket with it. You’ll need this for reinstallation. Clean off any oil and residue with a little brake cleaner, and make sure it’s in good condition.

Step 3: Prep the Differential Housing

Use a plastic scraper or razor blade to clean the mating surface of the differential. Ensure the area is free of debris, oil, and old gasket material. If you’re not using a reusable gasket, prep the surface for RTV sealant instead.

Step 4: Install the AFE POWER Differential Cover

Line up the reusable factory gasket with the AFE POWER cover, aligning all bolt holes. Hold the cover in place and hand-thread all bolts. Then tighten in a crisscross pattern.

Torque Spec: 12–16 ft-lbs. We recommend aiming for 14 ft-lbs using a torque wrench.

Step 5: Install the Magnetic Drain Plug

The AFE drain plug includes a magnet and crush washer. Wrap the threads with Teflon tape, insert the crush washer, and torque to spec with a quarter turn after snug to seal the washer.

Step 6: Add the Sight Glass

Wrap Teflon tape around the sight glass threads and tighten it securely into the designated port. This feature allows you to check oil condition—especially useful after water crossings.

Step 7: Fill with Gear Oil

Use 75W-90 synthetic limited slip gear oil. Fill through the level port until fluid just begins to drip out. If oil overflows, let it drain back to proper level to prevent internal pressure buildup.

Note: Some Jeeps may require a funnel or fluid pump depending on clearance.

Step 8: Install the NPT Level Plug

Apply Teflon tape to the 1/8″ NPT level plug, insert it into the fill-level port, and tighten securely.

Step 9: Install the Long-Reach Magnet

This long magnet reaches into the fluid to trap more metal particles. Add Teflon tape to the threads and install it into the upper port of the diff cover. Tighten with a ratchet.

Fitment Notes for Lifted Jeeps

If your Jeep has an extreme lift, you may need to roll the pinion upward, which can shift the fluid level. Always verify the oil level matches your specific setup. For a stock or mild 5-inch lift, using the level sight glass on the AFE cover is accurate.

Compatible AFE Diff Covers

• Rear Dana 44 – Fits 2018+ Jeep Wrangler JL
• Front Dana 44 – Installs the same as the rear
• Dana 30 & Dana 44 (2007–2017 JK) – Available in steel
• 2020+ Jeep Gladiator JT – Same cover as JL, includes sway bar spacers

FAQ

What gear oil does a Jeep Wrangler JL use?

Most Jeep Wrangler JLs use 75W-90 synthetic limited slip gear oil. Always check your owner’s manual for confirmation.

Do I need to re-torque diff cover bolts?

It’s a good idea to check bolt torque after a few heat cycles or your first off-road trip. Torque to 14 ft-lbs.

How much gear oil does the AFE POWER cover hold?

AFE covers add a bit more capacity over stock. Fill to the sight glass level for your application.

Does AFE POWER make a front diff cover for the JL?

Yes, the front Dana 44 cover installs exactly like the rear and features the same components.