If this doesn’t convince you…

[Scottie2Hottie]

Was it confirmed the rear differential needs the modifier fluid?

 

[RHOfan]

Was it confirmed the rear differential needs the modifier fluid?

Modifier fluid? You mean limited slip additive?

No, it’s not a limited slip diff & needs no additives…just the correct weight gear oil.

 

[Scottie2Hottie]

Skipping front differential. I’ve heard few people report that being worth the hassle. Even Blackstone reported it being in good condition for another forum member after 5K miles.

Doing the transfer case. It takes 1.9 qts of $60/qt fluid, so waiting on Amazon to deliver some 1/2” OD poly tubing, so I don’t spill any fluid & end up needing to buy a 3rd bottle. The fill plug is behind an exhaust pipe, so rigging the fluid bottles with a pointed cap & poly tubing.

Also, the transfer case fluid plugs appear to be steel (maybe aluminized steel?) that thread into a cast aluminum housing. Be very, very careful tightening those plugs into such a soft material. I’ve noticed BW (transfer case manufacturer) uses blue RTV to seal the plugs without using much torque. The torque specs I’ve found range from 15-18 ft/lbs, with breakage occurring above 22 ft/lbs.

So, I’ve also ordered some blue RTV, and plan to use a very gentle touch.

@RHOfan where did you find the fluid capacities? I search the Owners Manual and it only shows the fluid type; not capacity. I am getting my front & rear differential fluid changed along with the transfer case. I want to double check what service says.

 

[RHOfan]

@RHOfan where did you find the fluid capacities? I search the Owners Manual and it only shows the fluid type; not capacity. I am getting my front & rear differential fluid changed along with the transfer case. I want to double check what service says.

I don’t remember. I know the parts counter guy told me how many quarts I needed. I verified his number on ChatGPT, but it wasn’t accurate on fluid types, so not sure I trust that tool 100%. I also watched a YouTube video on TRX driveline fluid changes & the guy, who was a Ram tech, said the amounts needed.

Hope that helps.

 

[RHOfan]

Did the rear diff diff fluid yesterday and made a rookie mistake. Maybe jinxed myself by asking this thread earlier this week if the gasket is reusable.

Anyways, I drained the old oil, definitely grey color, smelled bad, then started pumping new oil in with an Amazon hand pump that worked pretty well. BUT, the end of the tube had a black plastic nozzle with little “keepers” on the end. That got pushed into the diff too far and when I pulled the tube out, the plastic nozzle fell off INTO THE FUCKING DIFF! Damn it! Got new oil, tried to find a replacement gasket but apparently only one dealer in CA has it and it’s nowhere near me. So I pulled off the cover, removed the plastic nozzle from inside the diff, reinstalled, and filled back up.

So far so good. Lesson learned. 20 minute job turned into 2 and a half hours

So, was the rear differential cover gasket re-usable? RTV-only?

 

[BLKRHO2169]

Did the rear diff diff fluid yesterday and made a rookie mistake. Maybe jinxed myself by asking this thread earlier this week if the gasket is reusable.

Anyways, I drained the old oil, definitely grey color, smelled bad, then started pumping new oil in with an Amazon hand pump that worked pretty well. BUT, the end of the tube had a black plastic nozzle with little “keepers” on the end. That got pushed into the diff too far and when I pulled the tube out, the plastic nozzle fell off INTO THE FUCKING DIFF! Damn it! Got new oil, tried to find a replacement gasket but apparently only one dealer in CA has it and it’s nowhere near me. So I pulled off the cover, removed the plastic nozzle from inside the diff, reinstalled, and filled back up.

So far so good. Lesson learned. 20 minute job turned into 2 and a half hours

Gasket is reusable. Same happened to me so dont feel bad. Youre not alone. Lol.. Clean Gasket real good and the surface and should be good to go.

 

[BLKRHO2169]

@RHOfan where did you find the fluid capacities? I search the Owners Manual and it only shows the fluid type; not capacity. I am getting my front & rear differential fluid changed along with the transfer case. I want to double check what service says.

Mine took about 2.5 qts before seeping out of fill hole.

 

[AirRyan]

No friction modifier needed. It’s a locker, not LSD.

Ram specifies synthetic, so that’s what I am using. There are only a few applications I can think of where standard oil might work better, but not in a modern diff.

From the RAM 2026 1500 owners manual.

 

[kaos_859]

Here's a document that may help DIYers.

 

[Scottie2Hottie]

Got mine serviced today. The front diff and transfer case fluid looked normal for new break in. However, just as others posted, the rear was BLACK and shiny. The tech said it was a damn good thing I brought it in at 5000k mark. Ram needs to address this.

 

[RHOfan]

Got mine serviced today. The front diff and transfer case fluid looked normal for new break in. However, just as others posted, the rear was BLACK and shiny. The tech said it was a damn good thing I brought it in at 5000k mark. Ram needs to address this.

Transfer case may LOOK fine, but Blackstone Labs confirmed sufficient silicone gasket/sealer contamination to justify a fluid change.

I changed mine with the Mopar branded fluid, which was $$$. I’ve since confirmed from several sources that it’s Mobilfluid LT.

 

[Drogon]

Does this post from this TRX forum translate to our RHOs, for the process and fluids used?

Differential and Transfer Case Fluid Change- My Observations

Here's what I learned after changing the front and rear differential fluid and the transfer case fluid today. Total cost was about $200. Half of that is the t-case fluid, which is Mopar proprietary. I generally followed this video, which is excellent: Always pull the fill plug first before...

www.ram-trx.com

 

[RHOfan]

Does this post from this TRX forum translate to our RHOs, for the process and fluids used?

Differential and Transfer Case Fluid Change- My Observations

Here's what I learned after changing the front and rear differential fluid and the transfer case fluid today. Total cost was about $200. Half of that is the t-case fluid, which is Mopar proprietary. I generally followed this video, which is excellent: Always pull the fill plug first before...

www.ram-trx.com

Yup. 100%, in my experience with RHO.

He says the transfer case fluid is Mopar proprietary. I used the Mopar stuff, but I’ve read from two sources that it’s re-packaged Mobilfluid LT. Do your own due diligence.

 

[Banger]

Is this rear differential fluid change easy to do without a lift? Is there enough space under the truck to work?

 

[BLKRHO2169]

Is this rear differential fluid change easy to do without a lift? Is there enough space under the truck to work?

Yes

 

[Banger]

Yes

Awesome. Thanks!!

 

[Banger]

How helpful are the “squeeze pouches” for this job vs using the fluid in the plastic bottles? I don’t see the Mopar brand offering in pouches, but Amsoil is.
Thanks in advance, all!

 

[eltaco]

I just did mine this weekend - really simple job.

Grab yourself a $10 oil pump on Amazon, and you’ll be good to go. I ended up using around 2.7qts for mine.

I had heated my diff up ahead of the change, and it flowed out really smoothly. I’d say my oil was opaque with a slight metallic sheen to it, but no large particles. I had 7k mi prior to the change.

 

[Banger]

I just did mine this weekend - really simple job.

Grab yourself a $10 oil pump on Amazon, and you’ll be good to go. I ended up using around 2.7qts for mine.

I had heated my diff up ahead of the change, and it flowed out really smoothly. I’d say my oil was opaque with a slight metallic sheen to it, but no large particles. I had 7k mi prior to the change.

Like this?

https://www.amazon.com/dp/B07CX4XKFH?tag=ramrho-20

 

[eltaco]

Like this?

https://www.amazon.com/dp/B07CX4XKFH?tag=ramrho-20

I went with this one. Half as many pumps, and it’ll save you a few bucks.

Amazon.com: Fluid Pump for Standard Quart Bottles - 10cc Per Pump Stroke， Transmission Fluid Pump with 3rd Hand Adapter，differential fluid pump Transmission Fluid 2025 upgraded model with strong suction power : Automotive

Buy Fluid Pump for Standard Quart Bottles - 10cc Per Pump Stroke， Transmission Fluid Pump with 3rd Hand Adapter，differential fluid pump Transmission Fluid 2025 upgraded model with strong suction power: Fluid Evacuators - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Also, don’t do like one of our BLACK RHO members (who will remain nameless) and drop the tube in your diff. Your friends here might not let you live that down.