Transfer Case Lubrication Question

[SyN]

I ran into a couple of Oil field Hot Shot fellas... One runs a 7.3L and one a 6.0L ... They are partners in their own company.... To make a long story short... They tow in 4WD alot!! For many miles at a time... in Mud and Snow...

They both have had Transfer Case issues... Until they were told to change from ATF to 5W-20 Synthetic Motor oil... Both these trucks have auto transmissions... That was I beleive they told me 3 yrs ago... Since the swap to 5W-20 they have had no issues with the transfer cases...

Have any of you heard of doing this switch from ATF to Motor Oil... They made the mention the 5W-20 was very close to the same Viscosity as the ATF hense no problems will occur... I think they mentioned most of the issues was due to heat... Which the 5W-20 synthetic will handle this better then the ATF...

I'm ignorant to the inwards workings of the transfer case...What makes it have to have ATF? My CJ-7 transfer case is very similar to the one in my 01 F250 and it uses 5W-30 with no issues and is way quieter and so much smoother operation...

Can anyone share some knowledge with me on this subject?

[NoRalPh]

I don't know about the specifics of the different abilities of the two oils, but I can tell you, there's really not much going-on inside the TC

There's no frictions, no real "shifting", no hydraulic application, just a slider and a chain....

Would make me think that as long as it can take the shear load, thin enough to get everywhere, not foam or attack the seals, it wouldn't be a really critical thing.

[zambonimaxx]

I could actually see that making a little bit of a difference, since it would be a bit heavier it may hang on the chain a bit more and get flung a little bit less. May take a bit longer to warm up though. Anyone have a Transfer Case Temp gauge? Where does it normally stay under 2x4 and 4x4? Willing to do a test?

~Phil

[jshalala]

yeah lets hear more on this. I can bet some people are going to say that it will gunk up and when it is cold not provide proper lube. ??

[SyN]

They also told me their trucks are very well maintained... Synthetics are used through out the trucks... Their loads average between 2k to 11k lbs being towed in 4WD for many miles at a time... Once they are off the highway and on the lease road it can be 2 miles or 35miles into location... 3/4 of that time in 4WD... They did also relay that very few lease roads are flat and smooth...As those of you in the oil field know... They are constantly going up and down very steep inclines...

I also have heard that a lot of duramax owners draining their T/C which are supposed to run ATF and running 5W-30 or 5W-20 synthetic as well...

All of this just got me thinking...Which I tend to do alot... But for those of us who tow in 4WD more often then others, if 5W-30 or 5W-20 synthetic is a better choice then ATF in our Transfer Cases I would like to find out and make the switch to help prolong the life of the unit...

I would like to match the viscosity of the ATF as close as possible... Which I really don't know about...But maybe a very robust 0W-30 synthetic would be better? I'm up for many suggestions and ideas... I'm thinking of draining mine before it gets much colder...Right now I have Amsoil Torque Drive in there and operation is smooth but very noisy once engaged and running...

[Term3]

Interesting, I wonder if the synthetic 5w20 is better then Ford's synthetic ATF fluid which we use.

[SyN]

Term: This is basically what I am trying to find out....---> Is motor oil such as 5W-20 or 5W-30 or 0W-30 synthetic better suited for the Transfer Case then ATF... I think the key is finding the motor oil that is closest to the Viscosity of the ATF...

I really think Motor Oil can lubricate better and handle the heat better then the ATF...
Which the 2 fellas I chatted with claimed the problems with their Transfer Cases were caused because of the heat generated/which we all know heat is caused by friction!!! Ok... Lets find a better lubricant!!!

What I don't know is--->Why are some Transfer Cases filled with Motor oil and Some with ATF? I know all Transfer Cases are not the same... But If our Transfer Case will operate and function properly with Motor Oil.... Why ATF?

[Term3]

Sorry I was assuming you meant regular dino ATF fluid and not the stuff used in the auto 5 speeds

[JEL]

That is an interesting idea, I know ATF-even synthetic- doesn't handle heat all that well, but synthetic motor oil like 5w-20 probably handles it with ease. That's what Honda specs for their new cars and I'm sure their engines get way hotter than our transfer cases. I bet it would work, a t-case is a simple system in itself, it gets plenty hot, but it's still a very basic design that probably just needs to stay wet.

[SyN]

As I said above...I am totally ignorant to the insides of our Transfer Case... I am really only now worried about the seals being compatible with the motor oil... How many seals are we talking about?

Does anyone think the seals will not know the difference between the ATF and the Motor oil... I know the chain drive will not...