Hey fellas,

I am fairly new to the diesel world, and I just rolled over 15k miles on my 07 5.9 ram. Owners manual says its time to change my differential fluid. I know I want to run royal purple synthetic. What are the benefits/disadvantages of 75-90w vs. 75-140w? How many quarts does it take to do both axles? And how complicated of a job is it to do it myself? Never done it before, and I'm looking for some pointers. Thanks for any info.

 

As far as doin the job it's not hard, easy if you have someone with a hoist, but it can be done at home in the shop. No gasket or gasket maker needed the diff covers have reusable gaskets. I just changed mine in my 05 and I used 75-90 synthitic. Royal purple make a good product and should be fine to use. I can't remember how much it took to do both diffs I can look at my notes when I get home. hope this helps you out.

 

What do you need a hoist for? Just crawl under there with an oil pan to catch the old oil. Take out all the bolts except for a couple at the top just loosen them enough to where the cover stays on until it drains. Then after it's drained remove the cover and wipe everything clean with some paper towels. Wipe the gasket clean put it back on, put the cover on, put the bolts back in. Tighten them up snugly in a crisscross pattern. If you must torque them no more than 18 ft lbs. Fill with oil to the bottom of the fill hole. Done... Dodge updated and recommends 75W110 as people running the 75W90 and towing were having problems with high temps buring the paint off the diff cover. So thicker would be better if you're towing. Lots of guys here running 75W140 go for it. I'm still running the 75W90..

 

I had to put the front of the truck on jack stands so the suspension would extended and I could get to the bolts easier. It's simple though, just don't over torque the bolts and you'll be fine. The front took just under 2 qts and the rear took just under 4. I used RP 75W90.

 

Hey thanks for the info everyone, keep the pointers coming.

I don't tow anything (not to say that I won't ever just don't have anything to tow right now) so my primary objectives are fuel economy and reduced wear and tear. Which weight oil would be better for that?

92'1stGen, I glanced at your signature, and was wondering, is 2qt/4qt what you put in your '92 or in your '06?

 

The front covers gasket is reusable? No gasket to clean off?

 

Where on paper is the 75/110 or the 75/140 being recomended by Dodge? Who's having high heat issues with 75/90? I've never found a post stating so.The 07 repair manual as well as the previous years only state 75/90.Source of info place.

 

I meant just under 3 for the front, just under 4 for the rear. That's in the 06. The 92' I never change the front as it has manual locking hubs so the front drivetrain isn't turning like the newer ones. That'll be changed on the 06 soon though.

 

Source for info was from here as were all the complaints I read about guys towing heavy burning the paint off their diff covers. Sorry I don't have a link but it was a TSB or whatever they call updates that says to run 75W110. I read the thread. I know it was here. Take that for what it's worth.

I would go with 75W110 even if not towing. I didn't know about the update when I changed my diff oil or I would have went with the 110. The difference in fuel economy between 90 and 110 is so negligble as to not be worth mentioning too many other factors that would have a bigger impact imo.

 

Ya I forgot about the front diff being a little tuff to get to as a couple of the bolts at the top of the cover are behind the tie rod,I think thats what is was anyways. and I didn't say you needed a hoist but its a much easier job to do when you can stand at eye level with the covers then on your back. Work smarter not harder! Guess I'm use to the fact that I have access to a hoist to service my truck.

 

To Hound Dog and Diesel Junky


I haven't seen anything from Dodge or AAM recommending a different fluid other than a GL-5 Synthetic 75w90 for the 9.25 and 11.5 AAM axles in our trucks. If anybody has a solid source for that I would like to see it too.

Not to say that a heavier weight fluid will hurt it....I don't know. But Dodge still recommends 75w90 on the 2500/3500 trucks. Heavier weight on the rear axles of the half tons, Dakotas and Durangos. See here-----> http://dodgeram.info/tsb/2004/03-001-04A.htm and look closely at the chart. Also gives the fluid quantities too when using the stock diff covers.

I think the burning paint problem is really only during break in. The axles get extremely hot (by design) until they break in. And I think that is why they also have a 15k change interval. Truth be known....you would prob be better off changing the fluid after the first 1000 miles....and then changing it like every 50k with a good GL5 syn 75w90. (Mobil 1 75w90 is what I use and I change it every 20k now...no problems so far at 85k miles)

..

 

Cheap paint on the diff.covers to start with.Mine has areas in the center that look burnt but its not.Even more so after a hitch ball mounted in the bed.Fliud can be TOO THICK and not lube correctly.My 1998 1500 calls for 85w140 and so does my 06 Mercury Gran Marquis.But not my 03 Dodge.

 

Wow, this slipped by me completely! I was looking at the 'Schedule A' in my owner's manual and it makes NO mention of axle fluid change! Anywhere!
Only 'Schedule B' mentions axle fluid every 15,000 miles. And no mention of it anywhere else in the owner's manual. No wonder Dodge has a lot of axle failures! Does anyone know of an official axle fluid change schedule other than Sched B? The 2007 owner's manual leaves a lot to be desired.

 

Harwill. Dodges have lots of axel failures? Where is referance made to such? Do you mean on these 2500/3500 diesels or on 1500s? PT Cruisers?

 

I couldn't agree more, my uncle tells me the same thing.