Dodge rearend differential schedules

[Panzerman]

I have a 2006 Dodge Ram 2500 4x4 and the manual requires 15,000 mile rearend changes. It also requires synthetic and I think this is way overkill. I bought the truck new and changed the rear rearend at 3,000 miles and it was nasty, it was dark gray and the inside of the cover was thick and cruddy with gook I used Mobil 1 75w90 and I changed both rears at 15,000 to keep it with the scheduled changes and keep the warranty intact. The back rear was a little dark, but nothing like the first time, the front rear end looked normal, some metallic, but overall not bad. I put Royal Purple 75w90 in both rears for the 15,000 mile fill and I have 26,500 on the truck now and Iam going to try Amsoil 75w90 in the 30,000 mile change. But I think Iam going to Let it in there till 60,000 and cook the books depending on the condition of the Royal Purple and how it looks. I think this is overkill, especially with high quality synthetic lubes. Most truck makers spec the rear end lube for 100,000 miles. I do tow about once a month with the truck and pull around 8,000 lbs, but not constantly towing and Florida is flat so its not like it gets a workout. Whats your take on these crazy specs, I have the lifetime warranty and dont want to give them any reason to void me, but this seems crazy.

 

[dave123]

I think I would be running a 75w140 with a 2500 and tow 8000 lbs.
Amsoil Redline M1 Schaeffer would be my picks. 75w90 to light in that app 30K change with any of the above.

 

[TrentMiller]

Well, i have a 06 jeep crd, and my maual says 15k front and rear with fully synthetic. I usualy do it at 15k.

Every time i drain and refill them, my front diff looks pretty bad, always dirty. Rear usualy looks ok. We off road alot, at least every weekend, around 100 miles or so in dirt, we camp hike etc and sometimes just hit the trails.

In my situation i ALWAYS worry about water contamination, so i don't mind the 15k.

I'm willing to bet that if your towing, you should be using a heavier weight of oil in at least your rear diff, even my manual says if towing, use 75-140 and i've only got a little 2.8L 4 cyl diesel. )(rated at 5klb us, 7klb euro)

The best way to know for sure is to get a used oil analysis on your rear diff, i'm willing to bet that with a nice 75-140 you can get at least 50k.

Something to consider is the cost of that diff. You don't have a filter or pump in there so if things get bad, they just keep getting worse. Your way better off changing it at 15k especially with your towing.

Uoa your 75-90 at 15k and see how it looks that may be your most affordable option, 140 weight usually costs more.

 

[Jim Allen]

That Dodge has the AAM 10.5 rear axle, right? Or the 11.5.I think it depends on which GVW. I am surprised by the 15K service interval and am at a loss to understand why. The big AAMs are reputedly very good axles. Why does Dodge feel the need to run such a low OCI. Makes me say, "Hmmm?"

High oil temps could be one potential reason. Still, I have been running diff temp gauges for years now on several different axles (including an AAM 8.5) and I don't see how the AAMs could run so much hotter than any others. They use a relatively mild 1.5-in hypoid offset, as do many other axle whose general running temps I know. They also do not have excessivly low oil capacities, which could be another high temp indicator. At or above 250F is the danger zone where, even with a good syn, oxidation is taking place at a high rate.

Given the towing situation you describe, I'd be surprised if you were exceeding 250F... and even if you do, it's a relatively short duration. Also, most of your break in has already occurred, so the metal contamination has slowed drastically from that original 3K nightmare oil scene (that was a good time to change it too!).

FWIW, if it were my truck, I wouldn't be afraid to stretch it to 30K at this point. And if it were my truck, I'd have a diff temp gauge on it, maybe even a high capacity cover like the Mag-Hytec. In my trucks, the cover knocked an honest 15 degrees off the running temp and added an extra few quarts of capacity (which also helps in the keeping cool category), as well as a cleanable magnet to catch and remove iron as it appears.

Run 75W90 if you can. If you get a gauge and find consistently high temps, above 210F (the viscosity rating point for the oil) then it might be time to go up to a 140 grade

 

[CourierDriver]

see below, thats all i know,,,worked for me .........

 

[Panzerman]

I dont think 75w90 is breaking down. I doubt its getting that hot either. Id be surprised if it exceeded 200 F.75w90 is what the manual specs and only synthetic. I think the jeep rear is a different set-up because I seen in the manual where a 1500 could use 75w140 but they spec to use only 75w90 for the Dodge 2500/3500 and no posi modifiers either. The rear end holds 2 1/2 qts, which I think is pretty much. Pulling hills with 8000 and level pulling is alot easier on everything. Ill probably gauge how that lube looks when I do the 15,000 mile service. In tri-axle coal trucks, you could let synthetics in the rear go 250,000 miles. Granted they held alot, but they got constantly abused too, strip jobs, constant weight, water, mud and alot of mountains. I cant think I could do anything comparable to that Dodge rearend to kill that lube in 15,000 miles.