I have a 2011 Ram 2500 diesel and I want to change my diff fluid change. I purchased 5 guarts of Mobil synthetic lubricant 75w-90. Is this ok?

 

Anyone out there ever changed the diff fluid?

 

Your owners manual tells you what kind of fluid you require in the diff. It also may or may not require the Diff additive if you have a limited slip axle. If you don't put the additive in, and it's required, you'll wear out the diff in no time whatsoever, and have to get it professionally rebuilt.

The weight of the diff oil is based upon your weather conditions, and the specs of the manufacturer. Most diffs will accept just about any type of gear lubricant weight, but some manufacturers will want their weight specs only.

I use the 75-140 in all my trucks, as it's pretty much good all year long. If I lived in Canada or Alaska, I'd use a lighter weight for added lubricity.

If your truck has a ton of miles on it, adding the cost of synthetic won't do you much good.... unless you live in a really hot climate, or a really cold climate, as synthetics protect better in those environments. Using it in any climate won't hurt anything, so your answer would be yes, it would be OK to use.

 

From page 572 of the 2011 owner's manual:

Front and Rear Axle – 2500/3500
Synthetic, GL-5 SAE, 75W-90 or equivalent. Limited-Slip 10.5/11.5 inch
Models, Rear Axles Limited slip additive is not required.

I'm a strong believer in that first (30k mile) fluid change. That stuff is nasty when it comes out of there.

 

Thank you for the information. I now have 28,000 on my truck now.

 

It seems that there is more owners involved with programmers,delets and exhaust. Not much on oil change.

 

I use the mobile 75-90 also, 11.5 AAM did the first change at 5000 miles, and have changed it at every 30k miles since, works great, my manual calls for 75-90 so thats what I use, I have the limited slip and you dont have to use the addative. all good, even at 30k miles it is still clean and looks great.

 

My dealer told me 75/140 full synthetic no additive

 

I filled the oil to 1/4" below the fill.I also noticed oil runnig out of a seal in the front. Today I have to call the dealer.
Next week the front oil will get changed.

 

If it's like my '03 (haven't done the '11 yet- soon though) the front diff cover is a pain to remove because steering parts are in the way. Some guys will claim heresy, but I just loosened the cover bolts and let it drain. Did not remove the cover so I was not able to inspect wear patterns in the gears and such. Something to consider....

Oh, and make sure you don't overt-orque the cover bolts, I believe they are speced at 16 ft/lbs, which isn't much. There are reports on here of them breaking off.

 

I did 30 lbs.

 

I have the maghytec rear diff cover, so I just take her for a drive, get it warmed up, pull the plug drain and then add to the overflow plug, does take more than the 5 quarts though.

 

I did my own rear/front diff fluid change out. Easy stuff, I use silicon for the gasket on the stock covers. I used 75W90 castrol full synth oil, been working good.

 

Yup, on the '07 I changed the oils(both diffs, xfer case and manual tranny) at 25k with full synthetic. I put the Mobil 1 75/90 in the diffs and amsoil in the tranny and xfer case. On the '12 I will do the same, wait till 25k and change all the fluids and go with a 50k fluid change after that.