Diff Fluid Weight

[SRBSpeed]

Looking to change the diff fluid on my 2500 for the first time at the 30K mark and the dealer told me to go with the 75w-140 instead of the 75w-90 like the manual recommends if you're towing. Any experiences with running 75w-140 with your 11.5" ring gear trucks and will it have any adverse effects on the diff? Both oils in question are Royal Purple Synthetic that's safe for the LSD in the rear.

Thanks in advance

 

[H3LZSN1P3R]

Use oem spec

 

[loveracing1988]

Looking to change the diff fluid on my 2500 for the first time at the 30K mark and the dealer told me to go with the 75w-140 instead of the 75w-90 like the manual recommends if you're towing. Any experiences with running 75w-140 with your 11.5" ring gear trucks and will it have any adverse effects on the diff? Both oils in question are Royal Purple Synthetic that's safe for the LSD in the rear.

Thanks in advance

The dealer is full of crap. I test these axles on a daily basis, they are designed for a certain fluid for a reason. If you look in the manual it should actually be 75w85 that goes in them. Either put that or a 75w90 and be done. When I did my 2500 I used redline but only because it was cheaper than OEM.

 

[H3LZSN1P3R]

The dealer is full of crap. I test these axles on a daily basis, they are designed for a certain fluid for a reason. If you look in the manual it should actually be 75w85 that goes in them. Either put that or a 75w90 and be done. When I did my 2500 I used redline but only because it was cheaper than OEM.

Most dealers are full of crap i had one service manager tell me the oilchange intervals were 12000km when manual says 24000km then he said because we are “severe duty where we live” so i proceeded to show him where it states severe duty is also listed at 24000km intervals he got mad and walked away lol

 

[Rockcrawlindude]

What does the manual say?
Use that.

 

[CdnHO]

My 2003 HO Dually had the 11.5 AAM axle in it. 4.10 ratio. My truck's miles was primarily towing. The diff started howling after a couple of year and Chrysler replaced the ring and pinion under warrantee. The dealer mechanic suggested going to 75W140 even though the manual recommended 75W90. I had been using the Mopar 75W90. Anyway I was somehow able to contact an engineer at AAM who was initially hesitant to comment since Chrysler warrantees the axle. Some back and forth ensued and he said when they fill the axle at the factory they don't know what environment they will end up in. Could be northern Alaska or Brazil. Since the 75W90 would be suitable for most purposes that what gets put in them. I pressed him further and told him my location and use. I asked him if it was HIS truck "what would YOU use?" He said "75W140". So that is what the tech at the dealership put in it. I have changed my own oil since using Redline synthetic 75W140 and 16 years later it was still quiet when I sold it. YMMV.

 

[H3LZSN1P3R]

My 2003 HO Dually had the 11.5 AAM axle in it. 4.10 ratio. My truck's miles was primarily towing. The diff started howling after a couple of year and Chrysler replaced the ring and pinion under warrantee. The dealer mechanic suggested going to 75W140 even though the manual recommended 75W90. I had been using the Mopar 75W90. Anyway I was somehow able to contact an engineer at AAM who was initially hesitant to comment since Chrysler warrantees the axle. Some back and forth ensued and he said when they fill the axle at the factory they don't know what environment they will end up in. Could be northern Alaska or Brazil. Since the 75W90 would be suitable for most purposes that what gets put in them. I pressed him further and told him my location and use. I asked him if it was HIS truck "what would YOU use?" He said "75W140". So that is what the tech at the dealership put in it. I have changed my own oil since using Redline synthetic 75W140 and 16 years later it was still quiet when I sold it. YMMV.

I know when they went to that axle in 03 the 4.10s were an issue i know a few people who had the same issue it was an issue with the gears themselves not the fluid

 

[CdnHO]

I know when they went to that axle in 03 the 4.10s were an issue i know a few people who had the same issue it was an issue with the gears themselves not the fluid

Not aware of that. However based on what I was able to find out I used the heavier oil and was more comfortable using it. Regardless, I never had another failure and I tow a 22K fifth wheel. And that was 6K over the rated towing capacity of the 2003. One of the reasons for ordering a new truck rated for 30K. That and OEM parts were starting to be hard to find for the old girl.

 

[SRBSpeed]

What does the manual say?
Use that.

Says use 75w-85 for the <=11.5” axles and 75w-140 for the 12”. About a thousand miles on the 75w-140 so far. Potentially a small MPG impact but otherwise no issues. I don’t think it will accelerate any wear or cause damage, just be harder to turn and therefor maybe more heat and lower mpg? I agree, the dealer isn’t the most reliable source...

 

[jdefoe0424]

Coming from a 1500 with the 3.92 which required 75w140 in the rear end. I was a little surprised to find most 2500s only required 75w90. Must be more cooling and oil capacity in these trucks vs the 1500s because they're bound to build up more heat based on the higher tow ratings.
I may just run the 75w140 anyways, we'll see. I will at least mix it for my first change because I have some sitting on the shelf already.

Sent from my Moto Z (2) using Tapatalk

 

[CdnHO]

View attachment 12556
Says use 75w-85 for the <=11.5” axles and 75w-140 for the 12”. About a thousand miles on the 75w-140 so far. Potentially a small MPG impact but otherwise no issues. I don’t think it will accelerate any wear or cause damage, just be harder to turn and therefor maybe more heat and lower mpg? I agree, the dealer isn’t the most reliable source...

Most fluids are "We recommend" while one is "Use only". There is a difference. At the end of the day, you paid for it, you use what you are good with.

 

[Brutal_HO]

My opinion is use what the book says if you live in the snow belt or above.

If you live in consistently higher temps and tow often/heavy, I'd step up from the lighter weight factory spec.

In my 04.5 2500 factory was 75W90 and I ran Amsoil Severe Gear 75W110 with great results. Gears looked factory fresh on the changes I did. Mostly a tow rig in the hot summers here in CO and NM.

 

[flatlander]

Mopar lists two gear oils for the 2019+ 2500 & 3500 axles. Part 68210057AB is labeled full synthetic GL-5 and needs the additive for limited slip differentials. Dealer sold me 68449546AA, which has the friction modifier for limited slip, but is not labeled GL-5 or even full synthetic. Is this oil safe to use?

 

[Rockcrawlindude]

Discussion just around the corner about lsd in these trucks

Limited slip=yes, friction modifier.....yes and no

so as the title states, 2020 PW limited slip yes, online manual says no friction modifier required, pdf say yes a friction modifier is required. So....anyone really know? Also is the limited slip really a limited slip or that psuedo-brake-controlled "limited slip"?

hdrams.com

 

[loveracing1988]

Mopar lists two gear oils for the 2019+ 2500 & 3500 axles. Part 68210057AB is labeled full synthetic GL-5 and needs the additive for limited slip differentials. Dealer sold me 68449546AA, which has the friction modifier for limited slip, but is not labeled GL-5 or even full synthetic. Is this oil safe to use?

What is the viscosity?

 

[flatlander]

Both are 75w85

 

[flatlander]

Show me what two parts numbers are approved - I am curious. Sounds like 68210057AB is one of them since it has the GL-5 requirement which is an additive package for hypoid gearsets. The friction modifier being added is quite normal - you can leave it out and the rear end will have a higher torque bias but may chatter on tight turns. I looked up the 68449546AA and that is specifically for axles with the ZF electronic limited slip. Was that one of the approved lubricants for your application?

Both came up searching store.mopar.com for gear lubricant for a 2020 Ram 2500. Fitment for the 68449546AA oil lists 2019+ 2500 & 3500s. The 68210057AB oil lists 2013+ 2500 & 3500s. Missing the GL-5 label and seeing the catalog describing 6844956AA for ZF-ELSD axles adds to the confusion.

 

[GBB]

I’m wondering if Ram recommends 75W/140 for the 12” axels due to the fact that duallys are likely to be used for heavy towing, hot shotting, etc. if you live in a colder climate where it gets -20 I would think 75W85 would be fine. 75W/140 would get awful thick setting overnight in colder temps.