Why ATF in transfer case

[Sunnyinhollister]

Originally Posted By: MolaKule
Originally Posted By: Or
Your post is kinda vague and I'm not sure if it's a question or what, or what your truck may really call for (what year?), but:

Some transfer cases want ATF to assure a specific clutch lock-up. If you substitute a different ATF or lube with a different weight, you might get a "better" shift/lock up based on your butt in the seat. That is because it is slipping the clutch plates together and it feels smoother. And while it is making your seat feel good, it is shearing the friction material off of the clutch plates as it slips them together slowly. Better feel, much shorter life.

I really would think this through hard before second guessing what the well-educated, thoughtful and dedicated engineers decided was the best for your particular system when they designed it and dictated the specs.

Again, I can't tell enough from your OP to get specific, but I encourage you to think it through to make sure your choice is indeed wise.

That paper I posted was for MT specific lubricants and are NOT to be used in Transfer Cases or ATs.


Out of curiosity why not? Assuming the viscosity is about the same and the transfer case does not have clutches, why not use a MTF if one has it handy? I realize the gains might be minimal.

Just curious.

 

[Greasymechtech]

If you don't have clutches, you can use any similarly viscosity fluid that can protect a gearbox. If the gearbox(transfer case) is a known lemon, you can go a little thicker. Just don't go too thick.

If you have a pump, it can blow out trying to move an overly thick fluid. Poor fluid pumping/flow, increased pump strain/slip, poor lubrication/cooling.....

Also, having a pump makes up for the poor circulation/splashing/climbing/cooling/lubrication issues when compared to a non-pumped gearbox.

Don't use overly thick gear/motor oil if you require ATF(or other thinner fluid) and have a fluid pumped gearbox.

Don't use thin ATF if you require thicker gear/motor oil and don't have a fluid pump.

Going full synthetic 'similar' fluid is a good upgrade.

Going thicker or real GL rating for lemons or worked x-cases is an option.

Going thicker thinner for hotter colder climates is another.

 

[MolaKule]

Originally Posted By: JFK
Like other's have said. Are you aware that Redline has some ATF's that have gear protection abilities equal to GL4/GL5 gear lubes?


Yes, well, contrary to what Redline states, there is no proof that their ATF's come anywhere near GL-X specs.

 

[MolaKule]

Originally Posted By: Sunnyinhollister
Originally Posted By: MolaKule
Originally Posted By: Or
Your post is kinda vague and I'm not sure if it's a question or what, or what your truck may really call for (what year?), but:

Some transfer cases want ATF to assure a specific clutch lock-up. If you substitute a different ATF or lube with a different weight, you might get a "better" shift/lock up based on your butt in the seat. That is because it is slipping the clutch plates together and it feels smoother. And while it is making your seat feel good, it is shearing the friction material off of the clutch plates as it slips them together slowly. Better feel, much shorter life.

I really would think this through hard before second guessing what the well-educated, thoughtful and dedicated engineers decided was the best for your particular system when they designed it and dictated the specs.

Again, I can't tell enough from your OP to get specific, but I encourage you to think it through to make sure your choice is indeed wise.

That paper I posted was for MT specific lubricants and are NOT to be used in Transfer Cases or ATs.


Out of curiosity why not? Assuming the viscosity is about the same and the transfer case does not have clutches, why not use a MTF if one has it handy? I realize the gains might be minimal.

Just curious.


While the viscosities may be close, they contain different additive packages.

 

[bulwnkl]

Originally Posted By: MolaKule
Originally Posted By: JFK
Like other's have said. Are you aware that Redline has some ATF's that have gear protection abilities equal to GL4/GL5 gear lubes?


Yes, well, contrary to what Redline states, there is no proof that their ATF's come anywhere near GL-X specs.


Fair enough.

Is there specific reason (proof?) to think they don't?

 

[MolaKule]

Yes.

1.) They don't have sufficient AW additive levels for GL-4,

2.) No FZG or other test has shown they qualify for a GL-4 or higher protection rating.

Redline makes excellent products, but this particular claim makes me cringe.

 

[bulwnkl]

Seems reasonable.

If they are generally honest and makers of quality products, what do you suppose would cause them to make such a claim if it's not close to true?

 

[ac_tc]

Chrysler says atf +3 can run twice as long as dex3 in a 242.( -98 Durango owners manual. )
atf+4 is a very good fluid that probably would meet a gl-4 designation.
use atf+4.

 

[MolaKule]

Originally Posted By: bulwnkl
Seems reasonable.

If they are generally honest and makers of quality products, what do you suppose would cause them to make such a claim if it's not close to true?


To sell the same product for more applications.

Again, they make a "claim" with no proof.


All they would have to do is use their MT additive package in their ATF base oil stream and wolla, they would have a 70W80 7.5 cSt MTF for those transmissions that use a fluid that require a fluid with an ATF viscosity.

 

[kmrcstintn]

I was thinking the same thing with my Jeep Liberty...it calls for ATF +4 in the transfer case, steering system, and transmission; guess I gotta find out if my transfer case is chain driven or has a clutch; my guess is multiple applications for a single fluid to keep things simple from logistics standpoint;

 

[Oro_O]

Originally Posted By: kmrcstintn
I was thinking the same thing with my Jeep Liberty...it calls for ATF +4 in the transfer case, steering system, and transmission; guess I gotta find out if my transfer case is chain driven or has a clutch; my guess is multiple applications for a single fluid to keep things simple from logistics standpoint;


Possibly it has both a chain and clutches. Not mutually exclusive.

The TC in my suv has a BorgWarner and it has a dbl. roller chain for power transfer, and clutches for engagement. It specs Dex III (pre DexVI unit). Same unit as used in many Jeeps. Don't know what's in yours specifically, but it's not stictly "either/or."

 

[HangFire]

Most every transfer case has a clutch, that's its basic purpose, to switch in/out power to the other axle. The question gets down to if the clutch(es) get actuated a lot or feathered.

For my Dakota part time 4WD, it's either engaged for long periods or not, so I'm more than confident in using the factory designated ATF+4 (from a Chrysler/Center for QA listed, certified source).

For the more exotic AWD applications, something more sophisticated might be desired... or not... ATF+4 is, by definition, a rather high quality fluid.