I use Amsoil engine oil and in the Diff's. It is actually cheaper than Mobil 1, and RP plus it tests far better and they ship to your door, saving gas money. To get the best price, just search online for a local sponsor, and register. They will pay your application fee, so you get jobber prices rather than retail. Then you order direct form Amsoi, using the registration number.
2006 GC Overland QD II
5.7 Hemi, Modern Muscle 85 mm CNC ported TB, Apexi super voltage stabilizer, Billet Tech. Catch Can, Koni FSD shocks/struts, SRT8 sway bars, Cooper Discoverer SRX 255/65/17, Amsoil fluids, Diablosport Intune CMR tuned by Hemifever tuning.