fluid for a np241d transfer case

[pjc360]

trying to decide what the best fluid to run in my transfer case would be. Right now it has atf+4 in it. But i have talked to a few people who tell me engine oil works way better in them. I know a guy who runs Mobil 1 10w30 oil with a quart of lucas oil stabalizer in his 241 nd he said it runs quiter now and engadges into 4wd much easier then it did with atf. Haas anoyone here ran engine oil in a 241 transfer case before? Transfer case i have is behind a chrysler A-518 transmission in a 1991 dodge ram half ton short bed truck. I do use the 4x4 quite a bit so the transfer case does see some use quite often. It makes sense that engine oil along with a bottle of oil stabalizer would lubricate better then atf in the transfer case. What do you guys think? stick with atf in it or switch to engine oil and oil stabalizer? and if i do go to engine oil does it matter if its a synthetic oil or a non detergent oil? like starigh 30w or something?

 

[Chris142]

That transfercase has an oil pump. It's designed to pump thin stuff like ATF. I certainly wouldn't go any thicker than a MTF fluid such as RP Synchromax.

 

[pjc360]

What about a 5w-20 synthetic or 5w30 synthetic? I have also read that atf evaperates out of these transfer cases lowering the fluid level wiout people knowing it.

 

[Chris142]

Why and how could ATF evaporate out of a transfercase that might hit 100f but not evaporate out of a trans @ 200f?

 

[pjc360]

i dont know? just what i read that overtime the atf will evaporate out of the transfer case vent and lower the fluid level without you even knowing it? dont know how true it is just read it. And i have read a bunch of people putting 5w-20 and 5w30 engine oil in them with a pint of lucas oil stabalizer just for better lubrication thru out the transfer case.