Engine oil for transfer case

[gomes512]

I hope this is the right forum.

Basically it's a '94 Jeep Grand Cherokee with the selec-trac 242 transfer case. The transfer case takes ATF+4 but recently a friend suggested that I use a synthetic motor oil such as 5w30 Amsoil. I test drove his Jeep before and after and noticed a marked difference in noise reduction and faster shifting between 2wd and 4wd. There are also some transfer case online retailers that only warrant their rebuilt cases with syn 5w30 not the OEM fluid.

I was hoping someone could recommend an oil but I am debating between 5w-20 and 5w30. I am thinking of 5w-20 since ATF+4 is already so low viscosity. I would try a 0w-XX oil but am worried about shearing. I don't want to lose the good cold flow characteristics.

I popped open a transfer case last week and saw that for the most part it contains gears, chain and bearings. Would a 5w-20 be ideal? I was thinking Pennzoil Platinum since it is easy to get and has a nice add pack.

I will be doing an initial flush as well to get the ATF out.

Any thoughts are appreciated!

 

[Tempest]

If you want thicker, go with a manual transmission fluid. Amsoil MTF or Redline MTL are good choices. These have real EP chemistry that motor oils don't have.

 

[Gary Allan]

I don't think he needs the added EP properties of a gear oil and I'm unsure of the effects on the metal inside ..maybe something with an MT rating. It's a chain driven t-case, not like a D300 gear driven. It has an oil pump too. I've used synthetic AFT in my wife's for around 50k now.

Funny, I never noticed a noise component to it

Amsoil ATD Torquedrive would could be an alternative.

 

[Shannow]

Most of my 4WDs have specified ATF if you've got an auto transmission, and gear oil if you've got a manual.

Same transfer case, vasty different lubes.

Message it sends me is to use what's convenient.

 

[MrCritical]

Gear oil would be a lot heavier that 5w20.

 

[Junior]

Would one want to use something that isn't energy conserving like what is used in a motorcycle transmission?

 

[Black_Thunder]

why not use a synthetic ATF?

 

[gomes512]

Well I don't really have a problem using ATF+4 which is synthetic isn't it? But the transfer case sure does shift a lot faster between 2WD and 4WD when using a synthetic 5w30, it's a world of difference.

Judging by the fact that simple motor oil can be used, I'm assuming the case does not require any type of friction modifiers in the fluid. Well at least it seems my particular model does not.

I'm afraid to use a gear oil as that would probably be to heavy. Plus it gets kinda cold in Chicago come winter time. I'm unsure of what viscosity an ATF+4 is but I'm assuming it's pretty low. That's why I was thinking of using a synthetic 5w-20 oil.

Schaeffer's or PP maybe?

Oh yeah and Gary you where right there is no noise, my friend had changed the front diff. fluid with a thicker synthetic one. I was hearing the front diff engaging. Still doesn't explain the faster shifts though.

 

[ccdhowell]

You may try Royal Rurple Syncromax. It's made to replace ATF and oil in transfer cases. I've used it before in a Chevy case and liked it. I'm using it now in a bike transmission, like it there as well. Chris