Hey guys this might seem like a dumb question but I have yet to find the breather line on my NP231 TCase under my cherokee. Help please!

 

On top if I'm not mistaken. Been awhile since I've had mine off

 

 

On my 91 it runs all the way up to the passenger side E12 bell housing bolt.

 

I'm still pretty lost :/ drivers? Passenger side?

 

Top of transfer case there is a vent tube similar to the picture Salad posted. From that location a vent hose will follow the transmission all the way up to the engine bay. I know on my 91 the vent tube is located on the passenger side E12 bolt on the bell housing. Your situation may be different because I am not familiar with the year of your Jeep.

 

Driver's side, it's above the front drive shaft. All NP231J cases are the same

 

Thank you so much! What oil do I use for this transfer case?

 

Any ATF you want. GM Dexron family, Ford Mercon family, Chrysler ATF+, any multivehicle stuff... 5w30 synthetic actually works quite well. If you have an AW4 transmission keep it easy and use D/M, then you only have one fluid to worry about!

 

What is D/M? And 5w30 in a transfer case? Really?

 

DM = dexron mercon III

 

And the 231 transfer case aren't designed for use with heavy gear oils.

 

D/M is, officially, a fluid that is compatible with the Dexron III/Mercon specification. GM stopped licensing a years ago to push the new spec, so all the bottles say "D/M" or "Dex/Merc". The ATF itself didn't change, just the right to use the name lol. Same stuff you put in your transmission (if you have an auto).

Yeah Rockland Standard gear found that synthetic 5w30 actually does better in these transfer cases. Under heavy use the ATF gets so hot it vaporizes out the vent tube! I'm not sure what the practical benefit is for the average user but it's certainly a workable oil. The lubrication requirements of the NP231 are not particularly advanced hehe

 

I knew it was something like that just wasn't sure. And perfect! Thank you! I have ALLDATA, but I'd prefer to take advice from the real world on some things haha.

 

That's correct. None of that junk in there.