In my 97TJ's with 5 speeds and my 98XJ with 5 speed I run redline MT90, it is a GL3-4 rated oil that has very low levels of sulfur in it, GL5,6 rated have high levels of sulfur which eat the synchro's in the asin trannies. The redline is also a synthetic which makes it much nicer in cold weather. Either that or stick with the dealer OEM oil.
For the transfer case, I run Mobil-1 ATF in all of my NP231's and the 242 in our 97ZJ.
If a gear lube says it meets GL2,3,4,5,6 ratings, like Coastal oil sold in advanced auto, they are lying, it either has sulfur to meet the 5 and 6 ratings or it does not.
If you have an auto tranny just go with what the owners manual tells you to.
For the NV3550 found in your 04...any sychromesh fluid... royal purple makes a synthetic sychromesh and so does mobil 1, pensoil, and valaline have sychromesh. I know the royal purple is full synthetic as with the mobil 1, not sure if the others are a full synthetic sychromesh.
For the t-case....I've never had a problem along with many other running Mobil 1 ATF <-- it's full synthetic.
and yes you run atf in the t-case.
the choice is yours of the product/company you want to use.
Royal Purple or Redline, depends on where you are in the country, you don't see Royal Purple here in the North East except at a few racing shops. Redline however has been showing up at most parts stores in the last couple of years. I got into a discussion with the manager at our local AA, now he stocks MT90 and it sells.
The only shop I know that sells RP is down in Dover/Rockaway NJ on Rt 46, they have the entire line of RP and Redline in stock.
Thats easy, GL3/4 Redline MT-90, it won't eat the bronze synchros in the tranny. Use a gl5/6 and it will start popping out of gear on you as the synchros wear. It's easy to spot when someone uses it too, the oil comes out a nice golden color, more golden then new.