Talked to the parts guy about transfer case and diff fluid. He looked up my Jeep's VIN# and their computer showed "Mopar ATF+4" for Transfer Case. They apparently do not carry single quart containers and he recommended I use any ATF+4 fluid. For the differential fluid, it showed "Mopar 75w-85" oil at $65/quart.
SYNTEC Full Synthetic Motor Oil 5W-20 5 Quart - SYN5-20-5QT. Part #: SYN5-20-5QT. Line: SNT. Check Vehicle Fit. Synthetic Motor Oil All Temperatures; Vehicles With The 5.7L Multiple Displacement System (MDS) Must Use SAE 5W-20 Oil; Failure To Do So May Result In Improper Operation Of The Multiple Displacement System (MDS) Manufacturer's Defect
Valvoline 5w20 full synthetic in the Grand Cherokee. Changed to synthetic at 1,100 miles. I change every 6 thousand miles. Change your oil at what ever interval gives you peace of mind. It's your Jeep, your money. Changing the oil every time you drive it won't hurt it. I use valvoline 10w30 in my 96 Cherokee sport and change every 3,000 miles. HT JLSrp.