drivetrain

Differential Cover Gasket

for 2007 Ram 3500 5.9L I6 Cummins · 4WD

Difficulty

Easy

Time

1.7 h

Tools

Steps

✓Fact-checked. Built from OLP's spec database, then independently fact-checked line by line with every correction applied. Master-tech sign-off by Chris Hackleman is queued. Cross-check torque values against the factory manual, and stop if anything looks unsafe. How our data is made.

This procedure covers removal and replacement of the differential cover gasket on the rear axle to repair leaks or perform differential service.

Warnings

⚠Gear oil may be hot if vehicle was recently driven. Allow differential to cool before starting work.

⚠Used gear oil can be slippery and difficult to clean. Work in well-ventilated area and dispose of fluid properly.

ℹ️The 2007 Ram 3500 uses an AAM 11.5" rear axle. Verify your axle type before ordering parts.

Tools required

3/8" drive ratchet and socket setEssential

Drain pan (minimum 6 quart capacity)Essential

Gasket scraper or razor bladeEssential

Wire brush

Brake cleaner or degreaserEssential

Torque wrenchEssential

Shop ragsEssential

Jack and jack stands (if needed for access)

Fluid transfer pump

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Parts

Differential cover gasket × 1 — Use OEM Mopar or equivalent for AAM 11.5" rear axle
RTV silicone gasket maker × 1 — Permatex Ultra Black or equivalent

As an Amazon Associate and Autel/ANCEL partner, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Fluids

75W-90 synthetic gear oil — 5.5 qt

Preparation

Park vehicle on level ground and engage parking brake
Allow differential to cool if vehicle was recently driven
If additional clearance is needed, safely raise and support the rear of the vehicle on jack stands
Position drain pan under differential cover
Clean exterior of differential cover and surrounding area to prevent contamination

Procedure

1
Remove differential cover bolts
Loosen all differential cover bolts in a crisscross pattern. Leave the top two bolts partially threaded to keep the cover from falling when the last bolts are removed. The cover is typically held by 10-12 bolts depending on the specific axle configuration.
2
Drain differential fluid
With the drain pan positioned below, carefully remove the remaining top bolts and gently pry the bottom edge of the cover away from the housing to allow fluid to drain. Once most fluid has drained, remove the cover completely and allow remaining fluid to drain from the housing.
3
Clean differential cover
Remove all old gasket material from the differential cover using a gasket scraper or razor blade. Be thorough but avoid gouging the sealing surface. Clean the cover completely with brake cleaner and wipe dry with shop rags. Remove any magnetic drain plug and clean accumulated metal particles.
4
Clean housing mating surface
Remove all old gasket material from the axle housing mating surface using a gasket scraper. Take care not to allow debris to fall into the differential. Use brake cleaner to remove all residue and oil from the sealing surface. Wipe the surface completely dry.
5
Inspect differential components
With the cover removed, visually inspect the ring gear, pinion gear, and bearings for unusual wear, damage, or metal shavings. Check the gear oil color and consistency for signs of contamination or water intrusion. Address any issues found before reassembly.
6
Install new gasket
Apply a thin bead of RTV silicone to one side of the new gasket and position it on the differential cover. Alternatively, apply RTV directly to the cover sealing surface if using a gasket-less installation (verify recommendation for your specific axle). Allow RTV to tack up for 5-10 minutes if manufacturer instructions specify.
7
Install differential cover
Carefully position the differential cover with gasket onto the axle housing, aligning all bolt holes. Install all cover bolts hand-tight. Once all bolts are started, tighten in a crisscross pattern to ensure even compression. The AAM 11.5" rear axle cover bolts should be torqued to approximately 30 ft-lbs (M8 fasteners). Tighten bolts gradually and evenly in a crisscross pattern to ensure the gasket is evenly compressed without over-tightening.
8
Fill differential with gear oil
Locate the fill plug on the front of the differential housing (typically on the driver side). Remove the fill plug and using a fluid pump, add 75W-140 synthetic gear oil until fluid reaches the bottom of the fill hole and begins to seep out. The rear differential requires approximately 4.0 quarts. Install and tighten the fill plug.

Reassembly

Ensure all bolts are properly torqued in a crisscross pattern
Verify fill plug is securely tightened
If vehicle was raised, carefully lower from jack stands
Wipe down differential cover and surrounding area to remove any spilled gear oil

Verification

Check for fluid leaks around the differential cover gasket immediately after installation
Start vehicle and operate in forward and reverse to circulate gear oil
After a short test drive, re-inspect the differential cover for any signs of leakage
Check fluid level at fill plug after test drive and top off if necessary
Monitor for leaks over the next few days of driving