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Hummer H1 Front and Rear Differential Cover, 12 Bolts

PML Part Number 11155

Includes bolts, fill plug and magnetic drain plug.

PML Hummer H1 Differential Cover, As-Cast
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PML Hummer H1 Differential Cover, Black
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No image available of a polish part.

Approximately one week from order date of polish finish part until part ships.

As-cast finish
Go To Cart
Black powder coat finish
Polished finish

Volume: approximately 0.5 quarts over stock

Dimensions: approximately 11.7 tall x 11.8 wide x 3.8 deep

On Hummer H1 the front and rear differentials are the same. This PML cover will fit both axles and works with standard undercarriage protection. 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.

Always check your vehicle to verify configuration and clearance before ordering.


1996 Hummer H1 stock front differential cover

PML designed this differential cover with:

  • Extra capacity
  • Fins and sand cast aluminum construction to dissipate heat from the fluid
  • Clearance for brake calipers and undercarriage protection
  • Wide gasket flange for a secure seal to the housing
  • Thick walls to add strength to the differential housing
  • Bolt on replacement for stock covers
  • Drain hole with magnetic drain plug included
  • Bosses that can optionally be machined for a temperature sending unit

H1 differential covers are similar to a standard Dana Spicer AMC Model 20 cover (PML part number 5048). The cover bolt pattern, shape, and fill hole do not match. We've also heard that this is a Torsen differential.

PML Differential Cover Compared to Stock

PML Differential Cover Part Number 11155 height compared to stock  PML Differential Cover Part Number 11155, compared to stock
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These images show this PML differential cover compared to the stock cover.


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.

2003 Hummer H1   2003 Hummer H1 stock front diff cover   2003 Hummer H1 PML differential cover on front
2003 Hummer H1 change differential gear oil and covers   2003 Hummer H1 rear diff cover distance to cage   2003 Hummer H1 with PML rear differential cover installed
Top row, from left to right: 2003 H1, stock front differential cover, PML front differential cover
Bottom row, from left to right: PML cover and supplies, on rear distance from PML cover to cage, PML cover installed on rear
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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.

2000 Hummer H1 Duramax   2000 Hummer H1 differential aftermarket brake kit   2000 Hummer H1 Duramax with PML differential cover
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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.

1996 Hummer H1   1996 Hummer H1, stock rear differential cover   1996 Hummer H1, pml cover installed on rear differential
1996 Hummer H1 stock front differential cover   1996 Hummer H1 front differential with PML cover   1996 Hummer H1 front differential with PML cover and undercarriage protection installed
Top row: 1996 H1, stock rear cover, PML cover installed on rear differential
Bottom row: stock front cover, PML cover installed before undercarriage protection is put back on, PML cover installed Click on image to view larger.

For a larger picture, please click one of the above images. A separate window will open showing a bigger picture. (The larger pictures take a minute to display.)

PML Differential Cover Features:

  • Increased oil capacity for cooler temperatures
  • Sand-cast aluminum with raised fins
  • Thick wall construction to add strength to differential housing
  • Thick gasket flange will not bend when bolts are tightened
  • Machined gasket surface for a secure seal using RTV or factory reusable gasket
  • Oil changes without removing the cover
  • All hardware provided, including magnetic drain plug

Learn more about finishes and construction of PML parts.