Why ATF in transfer case
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It's a lightweight fluid. Chain driven transfer cases just need to lubricate the chain and bearings. You could probably use 5w-20 or something in one without issue.
The 242, though, has some sort of mechanism inside (clutches?) that need a specific AT fluid I think.
The 242, though, has some sort of mechanism inside (clutches?) that need a specific AT fluid I think.
When used with an AT, the concern for cross contamination is eliminated. My manual trannie Tacoma calls for gear lube in the tranfer case, same as the gearbox.
They would be separate in this application so the fluids wouldn't be able to mix.
Given that the fluid in the transfer case lasts a long time and ATF does not cost that much, one minds well use what they specify. The transfer case is not cheap if it needs replacement.
Because they said so?
GM transfer case? My 2006 GMC calls for Dexron 3H in the transfer case and Dexron 6 in the transmission.
GM probably found that it was plenty durable enough and increased miles per gallon by 0.05 mpg, which helps their CAFE requirements.
GM probably found that it was plenty durable enough and increased miles per gallon by 0.05 mpg, which helps their CAFE requirements.
Not really sure of the why, but it obviously works just fine. I figure my ATF-spec'd transfer cases require lubrication of the chain pin rollers and maybe either an input and output bearing or bushing as well.
Electric shift transfer cases will not shift in cold weather with thick fluids..
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Originally Posted By: bubbatime
GM transfer case? My 2006 GMC calls for Dexron 3H in the transfer case and Dexron 6 in the transmission.
GM probably found that it was plenty durable enough and increased miles per gallon by 0.05 mpg, which helps their CAFE requirements.
The NP231s will explode if gear oil is used; they can not pump gear oil and will not properly lubricate.
GM transfer case? My 2006 GMC calls for Dexron 3H in the transfer case and Dexron 6 in the transmission.
GM probably found that it was plenty durable enough and increased miles per gallon by 0.05 mpg, which helps their CAFE requirements.
The NP231s will explode if gear oil is used; they can not pump gear oil and will not properly lubricate.
It is called commonality on the assembly line, one less part # in the system etc.
I have two NV242's and I run Amsoil MTF in the T-case.
The new venture gear T-cases are not picky on the fluids. TCU founder recommended 10w-30 synthetic back in the day for his rebuilt units for Jeeps.
ATF will not harm the T-case but a MTF is much better for the gear sets.
If you stick with ATF+4, change it frequently.
I have two NV242's and I run Amsoil MTF in the T-case.
The new venture gear T-cases are not picky on the fluids. TCU founder recommended 10w-30 synthetic back in the day for his rebuilt units for Jeeps.
ATF will not harm the T-case but a MTF is much better for the gear sets.
If you stick with ATF+4, change it frequently.
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Some have pumps. Others don't.
ATF pumps well.
ATF pumps well.
I tore apart both the 249 that was in the jeep and a 242 that I pulled from another. My OEM case had ATF its entire life, and was clean as a whistle inside. The replacement case has some type of oil in it, and did not look so good inside. I have a picture but don't know how to post. This was a real eye opener of ATF cleaning qualities. I did put +4 back in, and want to drain it to get any contaminants out. Both the 242 and 249 have pumps in them.
My F250 calls for ATF in both 5-speed and transfer case. It shifted horrible on ATF, and much better on an MTF like Pennzoil MTF or Valvoline MTF. They are only a bit thicker than an ATF but have all the antiwear goodies of a gear oil.
Long story short, I switched both sumps to MTF, and yes the chain drive transfer case has a pump.
MolaKules list below has plenty of options available inbetween ATFs and heavy gear oils.
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Here is an updated list of dedicated GL-4 and a few GL-5 MTL's, Updated 12/7/2014:
A. These MTL fluids are closest to a Kinematic Viscosity of 6.xcSt@100C (About the same viscosity as a DexronVI) and SAE 70W to 75W or so are:
1. Castrol Syntrans FE 75W,
2. BMW (Pentosin) MTF-LT-3,
3. Honda MTII or MTF 2.
4. Ford FML-XT-11-QDC
5. Volvo Manual Transmission Fluid (6.4 cSt) [Recommended for: type M65 5-speed with 6-cyl. engine, M66, MTX75 and MMT6 and of the type M56, M58 and M59 from and including model year 1996. Meets Ford specification WSSM2C200-D2]
B. The next higher viscosity MTL would be the 7.5 cSt@100C versions (About the same viscosity as a the original DexronIII/Merc)
1. Royal Purple's Synchromax
2. Ravenol MTF-2
3. Honda MTF
4. VW part number G052512A2
5. GM Manual Transmission and Transfer Case Fluid
6. BMW (Pentosin MTF 2) MTF-LT-1, 2
C. The next higher viscosity MTL would be Castrol Syntrans V FE 75W-80 8.0cSt
D. The next higher viscosity MTL would be BG Synchroshift II 8.2 cSt
E. The next higher viscosity is Mopar Type MS-9417 MTL 9.0cSt
F. Valvoline MTF Part Number 811095 9.2 cSt
G. The next higher viscosity MTL would be Pennzoil Synchromesh 9.3 cSt
H. The next group of MTL’s are in the 10.x cSt (SAE 75W80) range:
1. Redline MTL 75W80
2. Amsoil MTF (9.7 cSt)
3. GM Synchromesh’s
4. Volvo MTF 645
5. Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic MTF (Carries a GL-5 rating as well)
6. Lodexol (Morris Lubricants) MTF
I. The next higher viscosity MTL would be a 12.0cSt@100C and SAE 75W85:
1. Redline MT-85 – 12.0 cSt
J. The next higher viscosity MTLs in the 14-15 cSt ( SAE 75W90) range would be:
1. Amsoil MTG
2. Redline MT-90
3. Castrol Syntrans Multivehicle 75W-90
4. Castrol Syntrans Transaxle 75w-90
5. Ford XT-75W90-QGT (Carries a GL-5 rating as well)
6. Ford MOTORCRAFT® Full Synthetic Manual Transmission Fluid XT-M5-QS
7. Subaru Extra-S Gear & Transmission Fluid carries a GL-5 Rating because it is used in common sump driveline systems.
Edited by MolaKule (12/08/14 05:32 PM)
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Long story short, I switched both sumps to MTF, and yes the chain drive transfer case has a pump.
MolaKules list below has plenty of options available inbetween ATFs and heavy gear oils.
------------------------------------------------------------
Here is an updated list of dedicated GL-4 and a few GL-5 MTL's, Updated 12/7/2014:
A. These MTL fluids are closest to a Kinematic Viscosity of 6.xcSt@100C (About the same viscosity as a DexronVI) and SAE 70W to 75W or so are:
1. Castrol Syntrans FE 75W,
2. BMW (Pentosin) MTF-LT-3,
3. Honda MTII or MTF 2.
4. Ford FML-XT-11-QDC
5. Volvo Manual Transmission Fluid (6.4 cSt) [Recommended for: type M65 5-speed with 6-cyl. engine, M66, MTX75 and MMT6 and of the type M56, M58 and M59 from and including model year 1996. Meets Ford specification WSSM2C200-D2]
B. The next higher viscosity MTL would be the 7.5 cSt@100C versions (About the same viscosity as a the original DexronIII/Merc)
1. Royal Purple's Synchromax
2. Ravenol MTF-2
3. Honda MTF
4. VW part number G052512A2
5. GM Manual Transmission and Transfer Case Fluid
6. BMW (Pentosin MTF 2) MTF-LT-1, 2
C. The next higher viscosity MTL would be Castrol Syntrans V FE 75W-80 8.0cSt
D. The next higher viscosity MTL would be BG Synchroshift II 8.2 cSt
E. The next higher viscosity is Mopar Type MS-9417 MTL 9.0cSt
F. Valvoline MTF Part Number 811095 9.2 cSt
G. The next higher viscosity MTL would be Pennzoil Synchromesh 9.3 cSt
H. The next group of MTL’s are in the 10.x cSt (SAE 75W80) range:
1. Redline MTL 75W80
2. Amsoil MTF (9.7 cSt)
3. GM Synchromesh’s
4. Volvo MTF 645
5. Fuchs TITAN SINTOFLUID SAE 75W-80 synthetic MTF (Carries a GL-5 rating as well)
6. Lodexol (Morris Lubricants) MTF
I. The next higher viscosity MTL would be a 12.0cSt@100C and SAE 75W85:
1. Redline MT-85 – 12.0 cSt
J. The next higher viscosity MTLs in the 14-15 cSt ( SAE 75W90) range would be:
1. Amsoil MTG
2. Redline MT-90
3. Castrol Syntrans Multivehicle 75W-90
4. Castrol Syntrans Transaxle 75w-90
5. Ford XT-75W90-QGT (Carries a GL-5 rating as well)
6. Ford MOTORCRAFT® Full Synthetic Manual Transmission Fluid XT-M5-QS
7. Subaru Extra-S Gear & Transmission Fluid carries a GL-5 Rating because it is used in common sump driveline systems.
Edited by MolaKule (12/08/14 05:32 PM)
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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.
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.
A lot of guys run 5w-30 in the GM transfer cases, specifically the ones in the 3/4ton trucks. They claim the cases run cooler and have less trouble with fluid finding its way out. Either way they seem to live a long time as long as the pump rub issue is fixed before it becomes a problem (pump wears a hole in the rear case and leaks all the fluid out)
MolaKule
Staff member
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.
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.
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