PML Differential Cover for GM 8½" and 8 5/8" Ring Gear, 10 Bolt, Horizontal Fins Design
Part Number 10815
PML makes two differential covers for the GM 8½, 8 5/8 inch 10 bolt rear end. See both PML GM 8½" rear differential covers to compare.
Black powder coating
Click on the button under the bolt size you need to order the differential cover. Scroll down for more information on bolts.
Volume: 0.5 qt. over stock
Dimensions: See this pdf file, a separate window or tab will open
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 differential include the following:
Configurations vary. Always check your vehicle to verify differential and clearance. Police vehicles generally have less clearance.
GM 8.2 10 Bolt: These rear end covers can also fit on older vehicles with the GM 8.2 differential. For example:
See our GM 8.2 web page for more information.
PML GM 8.5 cover with horizontal fins and stock GM 8.2 cover show together. Bolts hole locations at 6 and 12 o'clock are slightly different.
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.
Temperature Sensor Port Option
The boss on the side can optionally be machined for temperature sensor for $45 additional (call to order machining and let us know your sensor thread size).
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.
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. Watch the video for more informations on checking your bolts.
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
These images show this PML differential cover compared to the stock cover.
Our thanks to everyone who choose this PML rear axle cover for their truck or SUV and emailed us pictures.
2011 Cadillac Escalade EXT
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.
2012 Chevy Avalanche 1500
David has a 2012 Chevrolet Avalanche 1500 which he uses to tow a travel trailer. He had to replace the bearings in the differential so he wanted to find a better way to drain and replace the fluid to avoid having to replace the bearings again. So he purchased a cast finish PML cover and powder coated it a shiny black.
David had a thermal camera and took thermal images of the stock cover and the PML cover. He took both images after towing a trailer for about an hour on a highway followed by 15 minutes of slower, steady driving. Ambient temperatures were 80F and 70F. David emailed us saying:
"I assumed that the stock differential and axle had plenty of heat-dissipating area, since the oil can flow all the way down both axle tubes. A few square inches of aluminum fins would not add much. The thermal images revealed a different story. The stock differential temperature was mostly 170-200 degrees F while the PML differential was mostly 140-150 degrees F.
Our thanks to David for sharing his thermal images and comments with us. The images are below:
Thermal image of stock differential cover temperatures, from a 2012 Avalanche
Thermal image of PML differential cover temperatures, from a 2012 Avalanche
PML differential cover, custom powder coated shiny black, on a 2012 Avalanche 1500
2003 Chevy Avalanche Z71
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 Chevy Avalanche Z71 4WD
Alvin measured and determined this PML cover would fit with pan hard and sway bars and decided on the cast finish. He loves his new PML differential cover.
2003 Avalanche stock differential cover and clearance to sway and pan hard bars
2003 Avalanche with PML differential cover installed
2003 Avalanche with PML differential cover, clears pan hard and sway bars
2010 Silverado 1500
Torrance Transmissions in California at 310-378-9217 installed this PML differential cover on a 2010 Chevy Silverado 1500 4x4.
2007 Silverado 1500
PML differential cover installed on a Chevrolet Silverado 1500. Ed selected the black powder coat finish for his differential cover. Click on image to view larger.
2010 Chevy Suburban 1500 4x4 Z71
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!!!"
2010 Chevy Suburban 1500
Ben installed this PML transmission pan on his Suburban. He also installed a PML transmission pan. This Suburban did not have any clearance issues because it is not a police vehicle.
For the installation, Ben removed the track bar and sway bar and modified the brake line bracket just a little, as it is retained by one of the cover bolts. (PML does not recommend this. See a qualified mechanic to ensure brake line safety.)
2010 Suburban 1500
2010 Suburban has clearance for PML differential cover
Another picture of the clearance to the track and sway bars with a PML differential cover on a 2010 Suburban
2010 Suburban PML cover installed
2014 Chevy Tahoe 5.3L
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.
2008 Chevy Tahoe 5.3L
Ian installed this cover on his 2008 Chevy Tahoe 5.3 Maggie TSV1900 supercharged at 12 lbs.
He also installed a PML transmission pan. See PML 4L65E deep pan for info on that pan and installation.
Note that a 2008 Tahoe Police Pursuit Vehicle (PPV) did not have the same clearance. The pan hard bar on the PPV model hit the fins on the PML cover.
2005 GMC 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.
2006 Hummer H3
PML drilled and tapped the cover for a 1/8 NPT. The aftermarket gage and sensor installed in the cover lets this H3 owner track his fluid temperatures while on the road.
PML 10 bolt differential cover on 2006 H3
Temperature sending unit installed in PML differential cover on a 2006 Hummer H3
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:
Learn more about finishes and construction of PML parts.
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