PPE Rear Differential Cover

AndrewF · February 15

I went ahead and changed my rear axle oil (with Amsoil severe gear) and also installed a PPE cover. Seems well made and has magnetic drain and fill plugs along with all hardware for install.

It ended up taking ~4.25 quarts to fill which is slightly more than expected. Cover adds .7 quarts to the factory 3.17 supposedly by being larger capacity, not a higher fill hole. Maybe the factory amount is assuming 1/2” below the fill hole.

I only have 10k miles on the truck but I wanted to start fresh with everything theoretically now broken in. Fluid looked clean but magnet had a decent amount of crap on it which wasn’t surprising.

bruceb58 · February 16

Service manual say 0" to 1/2" down so if you fill even with the hole you are fine. Who knows what the volume is at the two different levels but its not significant.

I bought a Banks cover and it is going to require 5+ qts. I bought into the hype of the shape of the cover on the Banks not causing aeration.

Edited February 16 by bruceb58

AndrewF · February 16

8 hours ago, bruceb58 said:

Service manual say 0" to 1/2" down so if you fill even with the hole you are fine. Who knows what the volume is at the two different levels but its not significant.

I bought a Banks cover and it is going to require 5+ qts. I bought into the hype of the shape of the cover on the Banks not causing aeration.

The PPE cover also talks about that so hopefully it keeps aeration to a minimum as well. It appears the insides look somewhat similar.

Another JR · February 16

With the action that goes on in a differential there is going to be a certain amount of aeration if any part of the gears runs below the fluid surface. . What’s critical, though, is whether the shape of the housing (including the rear cover) causes that gear contact to provide good distribution of the lubricant over the top of the differential and out to the wheel bearings. The rounded OEM covers are specifically designed for that. Some of the flat covers that focus on marketing fins do not achieve that proper distribution. That was shown by the Banks video with the clear covers. Better heat dissipation is great as long as you maintain proper lubricant distribution.

Chuck FB · February 16

I just wish GM would have retained the drain for both front and rear diffs, its almost a guarantee that diffs with no drain plug won't get serviced as often as one that is set up for easy oil removal. As to the cooling effect of the aftermarket covers, I can see that being a plus but I have to wonder how much cooling they are capable of, perhaps the Banks unit as some valid reasoning but I can also see on deep trenched mud roads/trails or during the winter with a deep snow and ice situation it would risk ripping those wings off. All depends on the terrain one would expect to encounter. Other than the easy drain part of these aftermarket covers, with a gas truck using the same 11 1/2 diff that the Duramax was using and still is using in the 3/4 ton trucks, what are the odds that the low powered gas truck will ever have a hot oil issue that would damage the diff. That's just my view point on it and living up here its not like there is too much of a worry of a hot diff for over half the year. Now if I was living in the southern states and pulling a load through 120 degree temps, I might see things differently !.

bruceb58 · February 16

6 hours ago, AndrewF said:

The PPE cover also talks about that so hopefully it keeps aeration to a minimum as well. It appears the insides look somewhat similar.

The Banks video showed a PPE with a pretty flat back which is not like the one you bought. They likely tested one for a different brand truck.

newdude · February 16

41 minutes ago, bruceb58 said:

The Banks video showed a PPE with a pretty flat back which is not like the one you bought. They likely tested one for a different brand truck.

PPE redesigned their cover a bit from the older flat one. Banks made that video series in 2018 when PPE still had those flat covers.

Ram and GM use the 11.5" AAM. Banks has two versions that fit different year ranges of the 11.5" AAM and also the 12" that GM uses.

Edited February 16 by newdude

AndrewF · February 16

1 hour ago, Chuck FB said:

I just wish GM would have retained the drain for both front and rear diffs, its almost a guarantee that diffs with no drain plug won't get serviced as often as one that is set up for easy oil removal. As to the cooling effect of the aftermarket covers, I can see that being a plus but I have to wonder how much cooling they are capable of, perhaps the Banks unit as some valid reasoning but I can also see on deep trenched mud roads/trails or during the winter with a deep snow and ice situation it would risk ripping those wings off. All depends on the terrain one would expect to encounter. Other than the easy drain part of these aftermarket covers, with a gas truck using the same 11 1/2 diff that the Duramax was using and still is using in the 3/4 ton trucks, what are the odds that the low powered gas truck will ever have a hot oil issue that would damage the diff. That's just my view point on it and living up here its not like there is too much of a worry of a hot diff for over half the year. Now if I was living in the southern states and pulling a load through 120 degree temps, I might see things differently !.

Yeah of all the "upgrades" to the truck the rear cover is probably more for aesthetics than actual improvement. The magnetic drain plug is nice but it really isn't that hard to pull the cover itself, especially now that these have reusable gaskets and you don't have to spend a ton of time cleaning gasket/RTV off the surface. These covers probably do keep it cooler but I haven't ever seen a rear diff burn out either.

Surprisingly I have never owned a GM truck that had a drain plug. 1972 C20, 1985 K30, 2000 1500, 2006 1500, 2009 1500, and now this 2024 2500. I don't know what GM trucks came with the drain plug but I wonder if they don't put one in so you have to pull the cover and clean the magnet. That is probably the most important thing.

Chuck FB · February 16

18 minutes ago, AndrewF said:

Yeah of all the "upgrades" to the truck the rear cover is probably more for aesthetics than actual improvement. The magnetic drain plug is nice but it really isn't that hard to pull the cover itself, especially now that these have reusable gaskets and you don't have to spend a ton of time cleaning gasket/RTV off the surface. These covers probably do keep it cooler but I haven't ever seen a rear diff burn out either.

Surprisingly I have never owned a GM truck that had a drain plug. 1972 C20, 1985 K30, 2000 1500, 2006 1500, 2009 1500, and now this 2024 2500. I don't know what GM trucks came with the drain plug but I wonder if they don't put one in so you have to pull the cover and clean the magnet. That is probably the most important thing.

I haven't touched my diffs yet on my 2025 due to low miles but I've sure cursed at trucks over the years with having to seal them up, tried a factory gasket which was just your typical paper gasket and what a joke that was ( and with a new factory cover if you can imagine ) and so most pickup diffs I have had to resort to silicone and sometimes something doesn't quite go right and it leaks so then have to do the job all over again. On an older chev 1/2 ton ( independent front end ) the front diff has a drain plug as its not designed with a cover but I've never worked on any domestic pickup that had a drain plug on the rear diff. I had a Toyota pickup long ago with solid axles and by design they had to have drain plugs and that was such a no brainer to service. Large trucks, anything I've ever worked on always has a drain plug and for years have had a magnetic drain plug as they are made to be serviced and sure they hold five or more gallons of oil and use a pail pump but its all straight forward.

I already knew from seeing newer GM trucks that the rear diff no longer had a drain plug but there were some years they did and I don't know the group of years but I got the idea that ended around the 2020 time frame give or take but the casting still has the embossed area where they tapped for the drain plug. I assumed the front diff would have a drain plug, well no it doesn't.

The question is what does the dealer or a shop do in draining the oil, I was surprised when the partsman at the local dealer who had been in the oil change pit prior said they suck out the front diff so he didn't even know if the front diff cover gasket was reusable or not, it actually said its not in their parts system and yet videos show different. But that just shows a dealer may be sucking a diff out and therefore that magnet strip never gets cleaned off in an instance like that, that's not what I see as proper dealer service practices.

bruceb58 · February 17

10 hours ago, newdude said:

PPE redesigned their cover a bit from the older flat one. Banks made that video series in 2018 when PPE still had those flat covers.

Ram and GM use the 11.5" AAM. Banks has two versions that fit different year ranges of the 11.5" AAM and also the 12" that GM uses.

PPE still sells some flat covers. I would never buy one. Here is one of them for the 2001-2019trucks

https://ppepower.com/collections/differential-covers/products/heavy-duty-aluminum-rear-differential-cover-gm-dodge

Edited February 17 by bruceb58