I have read some of the threads on this and just ended up confused - I have a 98 XJ w the NPG 231 transfer case. Need to know the right type of fluid to put in there. Preferred brands and purchasing locations appreciated.

Thank you!

 

The final answer is: Depends who you talk to.



Most people will tell you Dexron fluid. And it works very well. Was the Mopar factory fill.



NVG's preferred/suggested fill is actuallly 5w-30. It falls in the same viscosity range as the Dexron (tho it feels a bit thicker when it is cold). But it has more anti-foaming additives. So it stays inside the case instead of potentially misting its way up the breather vent.



Synethic versions of either the tranny fluid or motor oil are excellent options.


Choice is yours, man.



Joe

 

D3 ATF Brand of your choice. Just Shell/Castrol for me.

 

a rule we always used was 5/30 on tranys that use standard oils like 90w

and on the autos use automatic tran fluid to match the trany so if there were any transfer of fluid from the tc to the trans you would not have any negative effect

 

See this is where things get confusing - let's pretend you're talking to a baby guys. Seriously.

I have an auto 4.0. So combining the logic in the previous 2 posts - I don't want to use ATF in the trans and 5/30 in the tc because of risk of cross-contamination. So I should just go with the Dexron III.

It just gets worse when you actually are in the parts store. Some places don't even carry the stuff anymore - everywhere keeps telling me to get the ATF+4, which I don't want to start that discussion again - there are plenty of other threads on it.

 

just use whats in you trany

 

AW4-Dex merc III

NP231-Dex merc III

 

thats what I run but the 98 has the new 42re/aw4

 

Mike ... you should be using SAE 30 or 40 if you want to match the viscosity of 90 weight oil. Not 5-30. That's assuming you don't want to use a synthetic gear oil (with GL3 or GL4 rating).


Google up a viscosity chart ... 5-30 is in the same index as the ATF. If it was good enough for NVG ... it's good enough for me.



Black ....If you have the risk of "cross contamination" then you should be changing your seals. What would you do if it was a manual tranny? Live in fear of cross contamination? You'd have to be leaking out of the tranny ... and then leaking INTO the t-case (or vice versa). There is a little bleeder hole at the bottom for that very reason.



The 231 case is not very particular what lube it receives. I've drained 90 weight out of some cases ... filled with the correct fluid ... and they're still on the road. Just make sure there is fluid in there ... and it'll probably keep on rolling.




Joe

 

I was not trying to match viscosity
just
ATF to ATF
regular oil to regular oil

I'm not nitpicking the composition

one oil for both make your life easy

 

I just stick with what the owners manual specifies, if it came factory, its a good bet its safe to stick with!!

and i know my 99 calls for the dextron III and as far as in the parts places, just read the bottles, youll find the "new" version of the dextron I forget what its called but it will say for use in dextron III applications or something to that effect, just read read the bottles....thinking about it the other day at walmart there was a dextron VI or something and an atf fluid that was used in dextron applications, it wasnt a ATF+ though......like i said just read the bottles and youll find what youre looking for!!

 

x2 if that is what the factory put in that is what should be put back in, they did the research and know best. I have noticed that car quest makes a lot of fluids that many places don't carry anymore. Might want to check there

 

Like many have said, as long as you keep the vicosity the same, the 231 is a beast and can take any type of fluid.

However, personally, I use the Dex merc ATF+ in mine as well as in my transmission. you can pick this up at any auto parts store.