Harry,
All of these will work in your Jeep:
4.0L inline 6 cyl engine- 5w30 or 10w30
NSG370 6 speed manual transmission- Synchromax 1.5 liters
NP231 transfer case- Synchromax 1 liter
Dana 30 front axle and a Dane 44 rear- Max Gear 75w90 (front 1.2 or 1.9 liters/ rear 1.7 or 1.9 liters)
Have a great day and thank you for choosing Royal Purple.
Kyle Neal
Technical Sales Represenatative