Volume: approximately 0.5 quarts over stock
Dimensions: approximately 11.7 tall x 11.8 wide x 3.8 deep
Number of Bolts: 12
PML designed this differential cover for Hummer H1 and HMMWV Humvee. It fits both the front and rear axles and works with standard undercarriage protection and brake calipers.
- Extra capacity
- Drain and magnetic drain plug for easier servicing
- Fins and sand cast aluminum construction to dissipate heat from the fluid
- Bolt on replacement for stock covers
- Wide gasket flange for a secure seal to the housing
- Thick walls to add strength to the differential housing
- Bosses that can optionally be machined for a temperature sending unit
- Includes new mounting bolts, fill plug and magnetic drain plug
This differential cover has been installed on many Hummer H1 as well as M998 Humvee (HMMWV) vehicles. The front and rear differential are the same and this cover fits both.
No modifications to standard undercarriage protection needed. It is designed to slide between the brake calipers.
Always check your vehicle to verify configuration and clearance before ordering.
Our thanks to those who have emailed us pictures of their installations.
- 2003 Hummer H1
- 2000 Hummer H1
- 1996 Hummer H1
- 1989 Humvee M998 6.2L Diesel
2003 Hummer H1
Jason H1 Rescue in Texas installed front and rear differential covers on Jeff's 2003 Hummer H1 with a Duramax swap.
The front does not have a skid plate or protective cage covering it. The hardest part of the installation was getting the PML cover passed the winch control box.
With stock rotors (11") there was 1/4 to 1/2 inch clearance, no problem. A little tighter, but fine. The brakes have been changed over to an Alpha with 12 inch rotors. This provided a bit more clearance with the fitment of the PML covers.
On Jeff's H1, stock capacity was 2 quarts. With the PML covers, the capacity increased to 2.6 quarts per differential.
Jeff has seen a temperature drop of 10 degrees with the PML differential covers.
Images show: 2003 H1, stock front differential cover, PML front differential cover, PML cover and supplies, on rear distance from PML cover to cage, PML cover installed on rear
2000 Hummer H1
This 2000 Hummer H1 with a Duramax engine has an aftermarket brake kit so the brakes were larger than stock. To remove the stock cover and install the PML cover, one caliper was loosened, the PML cover slid on, then the caliper was retighted. No modifications needed.
1996 Hummer H1
Jose's Auto Service, 310-672-4253, installed this PML differential cover on the front and rear of a 1996 Hummer H1. Our thanks to Jose for all the pictures and choosing PML covers.
Images show: 1996 H1, stock rear cover, PML cover installed on rear differential, stock front cover, PML cover installed before undercarriage protection is put back on, PML cover installed
Video of Installation on Youtube: H1 Hummer Gets New Differential Covers.
1989 Humvee M998
Louis installed this cover on the front and rear differentials of his 1989 Humvee M998 6.2L Diesel. He emailed us that the covers fit well on front and back without any modifications and he likes the extra oil capacity.
1989 Humvee M998 Diesel
Humvee stock cover and PML cover
1989 Humvee rear differential with PML cover installed
1989 Humvee front differential with PML cover installed
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Aftermarket Brake Calipers
On Hummer H1 the front and rear differentials are the same. This cover fits both. It is designed to slide between the brake calipers.
On an H1 with an aftermarket brake kit with larger calipers, one of the calipers had to be loosened to remove the stock covers and install this PML differential cover. After installation, the caliper was retighted. No modifications were needed. We do not know which brake kit so there may be variations.
This installation is on a H1 with stock brake calipers.
Included With Cover
PML Hummer differential covers ship with new mounting bolts, washers, fill plug, and a magnetic drain plug.
Inside of Cover, Drain Hole, and Fill/Level Check Hole
Drain: Drain on bottom of cover for easy fluid changes. Magnetic drain plug included.
Inside: The PML cover features an open interior like the stock cover. The PML cover is round, following the same general shape as the stock cover.
Fill Hole: The fill/level check hole on the PML cover is at the same height as on the stock cover for an accurate fluid level. This hole is on the front of the cover for easy access, as seen in the above pictures. PML provides a plug for the hole.