If you read the owner's manual, it says that only GL-4 grade fluids can be used in the trans. So be careful not to put in cheap fluid, it eats away at the syncros.

The most recommended fluid I have seen is Redline.

Redline MT-90 alone or mixed 50/50 with Redline MTL in the transmission

Redline 75W90 in the transfer case/rear diff. (GL-5 grade, but ok for this application)