PML Transmission Pan Differential Cover Amsoil Fluids – Beat the Heat Photo Gallery
Beat the Heat
Edward A. Sanchez –
Oct 19, 2017
Photo 1/25 | PML Lead
Photo 2/25 | PML 02 | While any underbody work is made easier with a lift, with some jack stands, it’s possible to have enough clearance to work underneath the vehicle. Make sure you have a chock behind the wheel on the ground, and that the jackstands are rated to handle the weight of the vehicle you’re working on.
Photo 3/25 | PML 03 | The Avalanche has the same coil spring rear suspension design as the Tahoe and Suburban, meaning it also has a sway bar around the rear differential housing. If you’re installing the diff cover on a Silverado or Sierra, you won’t have to worry about this.
Photo 4/25 | PML 04 | The first step to give yourself some more working space around the rear differential is to disconnect and remove the rear sway bar. First unbolt the sway bar top endlinks.
Photo 5/25 | PML 05 | Then you can unbolt the lateral bushings, and remove the sway bar.
Photo 6/25 | PML 06 | Now we will have much easier access to the rear diff cover.
Photo 7/25 | PML 07 | As expected for a vehicle of this mileage, there was some weeping along the bottom edge of the cover. However, it appeared the leakage was over a long period of time.
Photo 8/25 | PML 08 | We loosened the stock diff cover bolts. Be sure to have a drain pan beneath the differential when you do this to catch the gear oil.
Photo 9/25 | PML 09 | Thankfully, there was minimal metal debris on the magnet of the stock cover, and the fluid was still translucent and didn’t smell burnt.
Photo 10/25 | PML 10 | The ring-and-pinion and G80 limited-slip mechanism looked in good shape for the mileage.
Photo 11/25 | PML 11 | We took a razor blade to scrape off any gasket or silicone from the diff housing.
Photo 12/25 | PML 12 | With the differential housing surface clean, we apply a bead of RTV silicone to the surface. It’s important that you apply the bead to the inboard side of the boltholes, and not get any in the boltholes themselves.
Photo 13/25 | PML 13 | We applied some silicone to the differential cover to hold the gasket in place while we installed it.
Photo 14/25 | PML 14 | We centered the supplied gasket on the diff cover, making sure the holes are lined up. Because the aluminum cover is thicker than the steel, PML provides new hex bolts that will secure the cover to the differential.
Photo 15/25 | PML 15 | Put a small amount of Loctite 242 or equivalent medium-strength thread locker on the end of the bolts. Go around the perimeter and tighten bolts to 20 ft-lb (240 in-lb). The drain plug is the same torque spec.
Photo 16/25 | PML 16 | To fill the differential, it helps to have a fluid transfer pump. These are generally available online or in stores for less than $20. We used Amsoil’s 75w-90 Severe Gear oil.
Photo 17/25 | PML 17 | PML says its covers increase the fluid capacity of the rear differential by 1/2 to 1 quart. Our differential took more than three full quarts until it started coming out of the fill hole—the usual indicator of max fill level.
Photo 18/25 | PML 18 | PML recommends tightening the fill plug to 12 ft-lb (144 in-lb).
Reinstall the rear sway bar.
Photo 19/25 | PML 19 | Even with its relatively slim size, the cover gives a higher fluid capacity, and the external finning is designed to dissipate heat more effectively.
Photo 20/25 | PML 20 | The transmission pan proved to be a little trickier to install than anticipated, because of some of the tight clearances around it. If you have a service lift, it could make this job much easier. We did it in a driveway with some jackstands, and were able to complete it, but not without some bloody knuckles and a few non-PG words. The first order of business is to drain as much of the old transmission fluid before removing the pan as possible. Thankfully, the transmission fluid was still in relatively good condition.
Photo 21/25 | PML 21 | As noted above, clearances around the transmission were a little tighter than anticipated. We ended up having to remove the shifter cable bracket to get the pan out.
Photo 22/25 | PML 22 | While we had the pan off, we replaced the transmission fluid filter. While there are a lot of similarities between the 4L60E and the earlier 700R4 transmissions, there are some differences. We got an ACDelco 24208576 “deep pan” filter. Note the notched corner.
Photo 23/25 | PML 23 | Like the differential cover, the transmission pan comes with new bolts to work with the thicker flanges of the aluminum pan. PML recommends tightening them in a crisscross pattern to 10 to 12 ft-lb (120-144 in-lb).
Photo 24/25 | PML 24 | We had to loosen the transmission crossmember and use a pry bar to get the thicker, larger PML pan in. We then reattached the shifter cable bracket, and tested the shifter to make sure the mechanism was working correctly.
Photo 25/25 | PML 25 | Once we had the new PML pan fully installed, we added Amsoil’s Signature Series automatic transmission fluid. With the engine running, we continued to check the fluid level, and added fluid as needed.