Mopar manual transmission fluid.

See this link: http://dodgeram.org/tech/transmission/nv4500_spec.htm

If you stumbled onto a NV4500 wow!

R.

Checking out the other number, look at this link:
http://www.tellico4x4.com/nv4500-tech-label.php

A 2wd NV4500. If Patrick is right, and the dually I drove was anNV4500,, you will just LOVE it in your truck. It's light-years ahead of my NP420. I was thrown by the first-gear synchro, didn't remember that NV4500s are synchro into all forward gears. IIRC, the earlier Dodge NV4500s were also synchronized into reverse.
The only problem with this tranny is the 5th gear problem, look it up.
There is a fix, though.

R.