NP231 synthetic transfer case fluid

[J33PTJ]

Jeep is a 97 4.0 with the ax15 and a np231 transfer case. I have a couple gallons of Castrol TRANSMAX ATF/CVT Universal full synthetic. This stuff is ok to use in the NP231 transfer case, right?
I’m using Pennzoil Syncromesh in the AX-15 manual transmission. It has kept the trans shifting perfectly for 24 years... But, if there’s something better on the market please let me know. Thanks

 

[xXDavidCXx]

transfer case requires AFT+4

 

[Jurassic Jeep]

Jeep is a 97 4.0 with the ax15 and a np231 transfer case. I have a couple gallons of Castrol TRANSMAX ATF/CVT Universal full synthetic. This stuff is ok to use in the NP231 transfer case, right?
I’m using Pennzoil Syncromesh in the AX-15 manual transmission. It has kept the trans shifting perfectly for 24 years... But, if there’s something better on the market please let me know. Thanks

You can safely use any ATF, within viscosity spec gear oil or even within spec motor oil in the NP231. The OEM 'requirements' were just to keep the fluid the same as the auto trans option for simplicity. For a splash system transfer case it just needs the proper viscosity, they'll all meet the temp requirement and no other negative side effects.

 

[Jurassic Jeep]

transfer case requires AFT+4

Any ATF, within spec gear lube or motor oil are all safe to use in the NP231.