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GM 8½" and 8 5/8" Ring Gear, 10 Bolt
Horizontal Fins, Differential Cover

P/N 10815

Differential Cover, GM 8.5 10 bolt Differential Cover, GM 8.5 10 bolt Differential Cover, GM 8.5 10 bolt, polished

As-cast finish
$165.00

8mm-1.25x21 bolts: Go To Cart

8mm-1.25x16 bolts: Go To Cart

5/16in-18x7/8 bolts: Go To Cart

5/16in-18x5/8 bolts: Go To Cart

Black powder coating
$215.00

8mm-1.25x21 bolts: Go To Cart

8mm-1.25x16 bolts: Go To Cart

5/16in-18x7/8 bolts: Go To Cart

5/16in-18x5/8 bolts: Go To Cart

Polished finish
$280.00

8mm-1.25x21 bolts: Go To Cart

8mm-1.25x16 bolts: Go To Cart

5/16in-18x7/8 bolts: Go To Cart

5/16in-18x5/8 bolts: Go To Cart

Click on the button under the bolt size you need to order the differential cover. Scroll down for more information on bolts.

General Information

Volume: 0.5 qt. over stock

Dimensions: See this pdf file, a separate window or tab will open

PML makes two differential covers for the GM 8 ½, 8 5/8 inch 10 bolt rear end. To see both options, go to both PML GM 8½" differential covers.

Applications for a PML GM 10 Bolt Differential Cover

This PML differential cover fits the rear end differential on many GM, GMC, and Chevrolet vehicles. Be aware that for each model and year there may be more than one rear axle possible. See also GM 10 bolt 7.5, GM 14 bolt 9.5, and GM 12 bolt 9.5.

Typical applications for this cover include the following.

½ Ton Trucks, 1979 to Current:

  • C10 & K10
  • C1500 & K1500
  • Silverado 1500
  • Sierra 1500

¾ Ton Trucks, 1979 to 1998:

  • C20 & K20
  • C2500 & K2500

½ Ton Vans, 1979 to Current:

  • Vandura
  • Express
  • Savana
  • G1500

¾ Ton Vans, 1979 to Current:

  • Vandura
  • Express
  • Savana
  • G2500

Full Size Blazer, 1977 to 1994

GMC Jimmy, 1977 to 1991

Escalade, Tahoe, Yukon,
1992 to Current (check panhard bar clearance)

Avalanche 1500

Suburban 1500, 1982 to Current

Hummer H3

GM 8.2 10 Bolt: These rear end covers can also fit on older vehicles with the GM 8.2 differential. For example:

  • 1966 Impala
  • 1960s Chevelle
  • 1966 Pontiac GTO

See our GM 8.2 web page for more information.

GM 8.2 with PML cover
PML GM 8.5 cover and stock GM 8.2 cover

4WD Front Applications: See PML Part Number 6077 for GM Front 10 bolt 8 1/2" ring gear differential found on some 4WD Chevy and GMC SUVs and trucks. PML part number 10815 and 6082 are for the rear differentials.

Always check your vehicle to verify differential and clearance.

Temperature Sensor Port Option

The boss on the side can optionally be machined for temperature sensor for $40 additional (call to order machining and let us know your sensor thread size).

Bolt Information

PML includes mounting bolts with all differential covers. PML provides bolts that are longer than the stock bolts since the flange on PML's cover is much thicker than stock. The bolts with the stock cover will not work.

GM has used four different bolts on these differentials so to complete your order, we need to know which bolts you have. These differentials have used both metric and standard cover bolts. The bolt length has not been consistent either. When ordering one of these covers, you will need to pull one of your stock bolts out (a top bolt is best) and measure the length and determine whether it is metric or standard.

  • Bolt length is measured from the underside of the head (where a washer would sit) to the tip. If the bolts are metric, the length will be 21mm or 16mm. If the bolt is standard, the length will be 5/8 inch or 7/8 inch.
  • Metric bolts will have 20 threads per inch, standard ones will have 18. Also, a bolt head with lines or letters on it is typically standard. A bolt with numbers such as 5.8, 9.8, 10.9, or 12.9 is likely to be metric.

We know this is a hassle, but we do not want to send the wrong bolts or charge everyone a lot of extra money to cover sending all possible bolts with each cover.

Gasket Information for a PML GM 10 Bolt Differential Cover

PML machines the gasket surface of our differential covers completely flat. The flange surface of the differential housing is also machined flat. A thin bead of RTV silicon sealant makes an excellent seal between two machined surfaces. If you prefer to use a gasket, we have had customers recommend the Fel-Pro RDS 55028-1 gasket.

PML Differential Cover Compared to Stock

PML Differential Cover Part Number 10815 height compared to stock  PML Differential Cover Part Number 10815, compared to stock
Click on image to view larger.

These images show this PML differential cover compared to the stock cover.

This image compares the depth of both PML GM 10 bolt differential covers and the stock cover. Click on image to view larger in a new tab or window.
PML GM 10 bolt Differential Covers depth comparisons

Installations

Our thanks to everyone who choose this PML rear axle cover for their truck or SUV and emailed us pictures.

Chevy Tahoe 5.3L, 2014

Georgio installed this PML rear differential cover on his 2014 Tahoe and his 2010 Silverado. His stock bolts were 8mm-1.25x21mm. He also installed a deep PML 6L80 transmission pan on his Tahoe. Our thanks to Georgio for choosing PML covers and pans.

2014 Tahoe with PML Yourcovers.com GM 10 bolt rear end cover    PML GM 10 bolt rear end cover on Chevy Tahoe, ground up view    PML GM 10 bolt rear end cover on Chevy Tahoe
Click on image to view larger.

Chevy Suburban 1500 4x4, Z71, 2010

The images below are of Mark & Tahoe's 2010 Z71 Suburban. Our thanks to them for emailing us the pictures. They also commented on the cover: "Fit perfect! Thank you very much!!!"

PML Yourcovers.com GM 10 bolt Differential Cover on a 2010 Suburban    Stock differential cover on a 2010 Suburban    PML rear differential cover on a 2010 Suburban
From left to right: 2010 Suburban, Stock Cover, PML Cover Installed
Click on image to view larger.

Chevy Avalanche Z71, 2003

Derek installed this PML differential cover on his 2003 Chevy Avalanche. The cover fit nicely behind the pan hard and sway bars. His Avalanche had the 8mm-1.25x21mm stock bolts.

2003 Avalanche Z71   Installing a PML cover on a 2003 Avalanche Z71   PML rear axle cover installed on a 2003 Avalanche Z71
Click on image to view larger.

Yukon, 2005

PML Yourcovers.com GM 10 bolt Differential Cover on a Yukon

PML differential cover installed on a 2005 GMC Yukon SLE. The finish on this differential cover is black powder coat. Our thanks to Scott for sending us the picture. Click on image to view larger.

Silverado 1500

PML Yourcovers.com GM 10 bolt Differential Cover on a Silverado

PML differential cover installed on a Chevrolet Silverado 1500. The finish on this differential cover is black powder coat. Click on image to view larger.

Cadillac Escalade EXT, 2011

Michael installed a polish finish PML differential cover on his Escalade. He put 3 coats of clear coat on it and jb welded a filter magnet to the inside which has 25lbs of holding strength. (Note that we at PML do not think the magnet is needed or necessarily a good idea since a magnet attached incorrectly could cause a lot of problems.) Michael removed some fin material since he had about 1/4" clearance and wanted to be safe if the rubber bushings flexed. Our thanks to Michael for all his feedback and pictures.
Escalade that has a PML differential cover    PML GM 10 bolt rear end cover on an Escalade    PML GM 10 bolt rear end cover with  magnet

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
  • 3/16-inch thick wall construction to add strength to differential housing
  • 3/8-inch 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.