MobilFluid LT for the BW 48-11 (4Auto) transfer case

[c3k]

Looking at the manual, page 515, it calls for MobilFluid LT for the Borg-Warner 48-11 transfer case (that has the 4Auto selection).

I'm going to drain and refill the differentials with Mobil 1 75w90. I've got the 3.21 rear diff. The front diff calls for 75w85 which is almost impossible to find, so 75w90 will work just fine.

I've got 5k miles on the truck and want to ensure all the drivetrain components have correct fill level - there've been far too many reports of underfilled diffs - and also to rid them of any break-in contaminants and swarf and whatnot.

But the transfer case calls for MobilFluid LT (a hydraulic fluid): I cannot find it available anywhere. (No, I have not yet called the Ram service/parts department.)

Any ideas where to find it, or an equivalent substitute?

Thanks.

 

[jdefoe0424]

I prefer AMSOIL fluids for all my vehicles, in this case it would be the Multi-vehicle ATF. They also have Severe Gear for differentials.
DM me if you're interested.

 

[c3k]

I prefer AMSOIL fluids for all my vehicles, in this case it would be the Multi-vehicle ATF. They also have Severe Gear for differentials.
DM me if you're interested.

Looking at the specs, I know that ATF is a type of hydraulic oil, but it seems very different than Mobilfluid LT (which seems like a typical hydraulic oil).

Since AMSOIL carries hydraulic oils, why the ATF instead?

 

[IvoryHemi]

I used this

 

[cj7]

RED LINE lists MT-LV 70W/75W GL-4 GEAR OIL as a substitute for Mobilfluid LT, and likely a more capable, modern lubricant

 

[GKIII]

RED LINE lists MT-LV 70W/75W GL-4 GEAR OIL as a substitute for Mobilfluid LT, and likely a more capable, modern lubricant

That's actually really good to know...

They also list it as suitable for the MOPAR fluid(s) as well.

 

[c3k]

RED LINE lists MT-LV 70W/75W GL-4 GEAR OIL as a substitute for Mobilfluid LT, and likely a more capable, modern lubricant

That's really great information! Thanks.

 

[c3k]

Further research turned up this thread at "Bob is the Oil Guy": https://bobistheoilguy.com/forums/threads/ram-1500-bw44-44-transfer-case.318859/

 

[cj7]

FYI, as of 9/1/21, AMSoil does not list any fluid as recommended for use in the 2020 1500 DT transfer cases.

 

[jdefoe0424]

FYI, as of 9/1/21, AMSoil does not list any fluid as recommended for use in the 2019+ 1500 DT transfer cases.

Interesting as it shows up for a 2019, but not 20+
edit: hmm...it seems as 2020 is the only one that doesn't show up.

 

[GKIII]

FYI, as of 9/1/21, AMSoil does not list any fluid as recommended for use in the 2019+ 1500 DT transfer cases.

Still shows for me:

 

[IvoryHemi]

The OE fluid I drained out can best be described as hydraulic oil.

No way I would put ATF in there

 

[GKIII]

The OE fluid I drained out can best be described as hydraulic oil.

No way I would put ATF in there

The OE fluid is a heavy duty trans fluid + gear oil...which makes sense considering the 48-11 is a clutched system.

The Amsoil and Redline alternatives actually have very similar characteristics to MobilFluid LT at operating temperatures. There is a difference in Brookfield Viscosity @ -40C (Brookfield Viscosity is a measure of dynamic viscosity by rotating a spindle in a fluid sample and measuring a fluid's resistance to that rotation). The lower the number, the easier it is for something to move in that fluid. In this case lower = better @ -40C.

This is one of those areas where RAM/Stellantis didn't require a spec, but recommended a specific brand of fluid. They can't deny your warranty here if you go with a similar fluid unless they provide the Mobilfluid LT for free (which they don't, they sell it to you in unicorn tear-level priced quart bottles).

 

[cj7]

Still shows for me:

View attachment 104280

Not sure where that came from - here’s what the website says when I do it for my truck

 

[cj7]

The OE fluid is a heavy duty trans fluid + gear oil...which makes sense considering the 48-11 is a clutched system.

The Amsoil and Redline alternatives actually have very similar characteristics to MobilFluid LT at operating temperatures. There is a difference in Brookfield Viscosity @ -40C (Brookfield Viscosity is a measure of dynamic viscosity by rotating a spindle in a fluid sample and measuring a fluid's resistance to that rotation). The lower the number, the easier it is for something to move in that fluid. In this case lower = better @ -40C.

This is one of those areas where RAM/Stellantis didn't require a spec, but recommended a specific brand of fluid. They can't deny your warranty here if you go with a similar fluid unless they provide the Mobilfluid LT for free (which they don't, they sell it to you in unicorn tear-level priced quart bottles).

Viscosity is but one characteristic of a lubricant.

I wouldn’t put an ATF in a transfer case unless the OEM specified it was appropriate.
Mobilfluid LT application guide says “Do not use in passenger car automatic transmissions”.
AMSoil datasheet for their multivehicle ATF says “Not for use with Ford Type F applications”.
Mobilfluid LT “Suitable for transmission applications requiring Type A (Suffix A), Dexron, and Type F fluids“

SO, something is different. While a transfer case does not impose especially difficult requirements on its lubricant (aka you could probably get away with a bunch of different things in there), an ATF that does not say it is a replacement for the specified fluid, or lists the specific application, may not be your best bet.

As for warranty, I agree with the premise that you should not have to use their brand, but Magnuson Moss does say the OEM can require a specific brand/model/part for maintenance, if they can demonstrate that item is uniquely able to fulfill requirements. They could never do that, but nobody’s gonna spend the money to take them to court and make them try.

Dealer: “Warranty denied - sue us.”

 

[GKIII]

Viscosity is but one characteristic of a lubricant.

I wouldn’t put an ATF in a transfer case unless the OEM specified it was appropriate.
Mobilfluid LT application guide says “Do not use in passenger car automatic transmissions”.
AMSoil datasheet for their multivehicle ATF says “Not for use with Ford Type F applications”.
Mobilfluid LT “Suitable for transmission applications requiring Type A (Suffix A), Dexron, and Type F fluids“

SO, something is different. While a transfer case does not impose especially difficult requirements on its lubricant (aka you could probably get away with a bunch of different things in there), an ATF that does not say it is a replacement for the specified fluid, or lists the specific application, may not be your best bet.

As for warranty, I agree with the premise that you should not have to use their brand, but Magnuson Moss does say the OEM can require a specific brand/model/part for maintenance, if they can demonstrate that item is uniquely able to fulfill requirements. They could never do that, but nobody’s gonna spend the money to take them to court and make them try.

Dealer: “Warranty denied - sue us.”

The MM Act has a lawyer fee shifting provision (as in, you can claim lawyer fees if you win against the manufacturer). Unless Stellantis has an exception on file for Mobilfluid LT (in which case their lawyers would use "requires" vs "recommends" in regards to that specific product in the manual), it's a pretty open and shut case.

The real challenge is convincing a lawyer that your case is worth their while.

Also, AMSOIL does specifically state that ATF is a replacement for the matching MOPAR fluid part number (which is repackaged Mobilfluid LT) in the product data sheet. So there's that.

It's also not unusual for different fluids to have different application crossover. The Amsoil ATF has friction modifiers in it, which is the likely reason they note against use in Type F applications. The 48-11 transfer case isn't a Ford Type F application, so moot point.

All I'm saying is that there are other options out there, especially since Mobilfluid LT can be difficult to find. I would personally go with Redline's MT-LV 70W/75W and call it a day.

 

[GKIII]

Not sure where that came from - here’s what the website says when I do it for my truck

View attachment 104347

Yeah I don't know what to tell you here, still shows for me on their website.

 

[cj7]

The MM Act has a lawyer fee shifting provision (as in, you can claim lawyer fees if you win against the manufacturer). Unless Stellantis has an exception on file for Mobilfluid LT (in which case their lawyers would use "requires" vs "recommends" in regards to that specific product in the manual), it's a pretty open and shut case.

The real challenge is convincing a lawyer that your case is worth their while.

Also, AMSOIL does specifically state that ATF is a replacement for the matching MOPAR fluid part number (which is repackaged Mobilfluid LT) in the product data sheet. So there's that.

It's also not unusual for different fluids to have different application crossover. The Amsoil ATF has friction modifiers in it, which is the likely reason they note against use in Type F applications. The 48-11 transfer case isn't a Ford Type F application, so moot point.

All I'm saying is that there are other options out there, especially since Mobilfluid LT can be difficult to find. I would personally go with Redline's MT-LV 70W/75W and call it a day.

Good points. I guess lubricant tech has gotten so good that one fluid can fulfill the requirements of several different older ones.

And I plan on using Red Line MT-LV as well.

 

[jdefoe0424]

@cj7 @GKIII

I had an email exchange with AMSOIL tech support...in the 2020's Stellantis calls for the ATF Mobilfluid LT.
For 2019 and 2021 it's the "Briggs Warner specification."

Why the change...who knows, I wonder if it could have been something to do with the clutches overheating during heavy 4x4 use(I remember seeing several of these posts in the past). SO, they decided to change the spec for one year as an interim fix until they sorted the issue correctly...I don't know.
Theoretically, you could use the AMSOIL multi-vehicle in the 2020 1500's as we all know the transfer case is identical to the 2019 and 2021...AMSOIL themselves does not recommend it...but I seriously doubt you will see any issue by running it.

 

[cj7]

@cj7 @GKIII

I had an email exchange with AMSOIL tech support...in the 2020's Stellantis calls for the ATF Mobilfluid LT.
For 2019 and 2021 it's the "Briggs Warner specification."

Why the change...who knows, I wonder if it could have been something to do with the clutches overheating during heavy 4x4 use(I remember seeing several of these posts in the past). SO, they decided to change the spec for one year as an interim fix until they sorted the issue correctly...I don't know.
Theoretically, you could use the AMSOIL multi-vehicle in the 2020 1500's as we all know the transfer case is identical to the 2019 and 2021...AMSOIL themselves does not recommend it...but I seriously doubt you will see any issue by running it.

Thx for the info. I have no doubt you heard what you heard from AMSoil, but I do highly doubt what they said. The Borg Warner spec calls for mobilfluid LT, so seems like circular logic. More likely, the guy didn’t know anything more than some story somebody told him, that in reality, wasn’t true (and he or she just didn’t know any better).

I used to be a fan of AMSoil, but have come to be skeptical of their integrity. More and more I see carefully worded comparisons and highlights of only certain obscure specs (we flow better than X - but measured at -40), and now no longer use AMSoil. Their unwillingness to submit to outside bodies for some important certifications sealed the deal. I’ve come to use Red Line more, and a few euro-made brands (where synthetic really means synthetic, not like here).

But each his own...