Getting set to change my diff fluid before the summer camping season here. Noticed that the manual calls for ATF in the transfer case. Can anyone shed some light as to why ATF and not a gear-type oil in there ?

 

Less resistance-helps with mileage.....I got 198,000 on my last jeeps transfer case filled with Dexron ATF, no issues. Sold it and the people are still running up and down the roads

 

Simply cause the factories can't make up their frikkin minds. When I was at GM, one would have ATF, the next gear oil. I think it's all that bad crack the engineers are smokin.

 

The gears in the T-case are not stressed the same way as in the transmission, and especially in the differential. The T-case has a helically cut planetary gear set. There are many more gear teeth engaged at any one time to share the load. The lighter ATF+4 is adequate for this application.

The owner's manual requires ATF+4 in the T-case. Probably because it is used in the automatic transmission, and Chrysler gets royalties from other companies to be certified to make ATF+4. I can see ATF+4 being required in the tranny because of the additive package for the application, but it would seem the t-case would do just fine on any light oil.
Still, I would go with what the book says.

Can you imagine how difficult it would be to engage 4wd if a heavier oil was used?

 

too true...too true

 

if designed properly it could run on corn oil

 

Thanks guys. It has nothing to do with the hydraulic properties of ATF, or its ability to suspend and hold dirt particles, then? I would have thought that a heavier, stickier gear oil would have been more applicable, given the transfer gears spend a large proportion of their time (or their whole life, in some cases) idle and unused.
I'll stick by the book and use ATF 4, though.

 

all my truck have reqiured ATF from my 1980 dodge to my 09 wrangler auto or manual all required ATF my 1981 chevy required it 4 the manual trans even.