if you enter the amsoil site from this link I'll get the sale: http://wagoneers.com/AMSOIL/ (please use customer # 283461 if you call) once in the site, in the center of the screen there is a product selector, enter year, etc. and it'll tell you exactly what is best. If you're experiencing oil consumption or live in a high temp area I'd say go with a slightly higher weight. Engine Oil Grade 1......API* SAE 0W-30 Synthetic Signature Series Oil SAE 10W-30 Synthetic Motor Oil I wouldn't use the XL (didn't include that line), it's a cheaper blend intended for minute lube places, extends to 7,500 miles... not worth it. the real stuff will go 25,000 miles or more. I have run my Diesel Mercedes at 17,000 and 24,000 before changing. The last change was over 24,000 miles and three years... I ran an analysis after the 17,000 mile run and it came back with almost all A's, just one B. Gas engines are less harsh on oil, especially if fully warmed up and fuel injected. You can use oil analysis if you are curious or concerned. I'd say you could easily go two or three years, maybe changing the filter once a year. A gas engine should easily so 25,000 miles if you let it warm up whenever used, the only issue with a non-warmed up engine is condensation and water buildup, which can get quite nasty. :) Since you're in a humid climate this could be an issue... full warmups will reduce trouble. (if you're looking for economy, go with the 0w30, that's what I'm running in my 4.7L V8 WJ Grand Cherokee... have reached 21.3 mpg with it!) you'll also need the Oil Filter: EAO42 Absolute Efficiency Oil Filter the ATF is: ATFQT-EA Synthetic Universal Automatic Transmission Fluid : (1) quart bottle hope this helps... thanx, john 1991 Jeep Cherokee 4.0L HERE's the listed CAPACITIES: CAPACITIES Engine, with filter..........6.0 quarts[1] Cooling System, Initial Fill..........12.0 quarts AMSOIL Antifreeze and Engine Coolant Automatic Transmission, Initial Fill..........4.0 quarts[2] Automatic Transmission, W/ AW-4 Initial Fill..........4.0 quarts[2] Automatic Transmission, Total Fill 4 speed AW4..........8.5 quarts Manual Transmission, AX-5 2WD..........7.4 pints Manual Transmission, AX-5 4WD..........7.0 pints Manual Transmission, AX-15..........6.8 pints Differential, Rear..........3.8 pints Differential, Front..........2.5 pints[3] Transfer Case,231..........2.1 pints Transfer Case,242..........3.0 pints Transfer Case,247..........3.4 pints Transfer Case,249..........3.4 pints 1. After refill check oil level. 2. With ENG at operating temperature, shift through all gears. Check fluid level in NEUTRAL and add fluid as needed. 3. 1984-1992 Models with command-Trac, add 5 oz of 75W-90 GL-5 to shift motor housing opening. TORQUES Oil Drain Plug.....30 ft-lbs Transfer case Alum Case Fill Plug.....18 ft-lbs Drain Plug.....18 ft-lbs Transfer case Steel Case Fill Plug.....35 ft-lbs Drain Plug.....35 ft-lbs Manual Transmission Fill Plug.....27 ft-lbs Drain Plug.....27 ft-lbs ----- ---------------------------------------------------------------------- Snohomish, Washington -o|||||o- where Jeeps don't rust, they mold http://wagoneers.com ** http://wagoneers.com/FSJ/Omega/ ** ----------------------------------------------------------------------