From the 2005 WK Owners manual
http://www.jeep.com/en/owners/manuals/
FLUID CAPACITIES
Fuel (Approximate)
20.6 Gallons 78 Liters
Engine Oil with Filter US Metric
3.7 Liter Engine (5W-30, API Certified) 5 Qts 4.7 Liters
4.7 Liter Engine (5W-30, API Certified) 6 Qts 5.7 Liters
5.7 Liter Engine (5W-20, API Certified) 7 Qts 6.6 Liters
3.7 Liter Engine (5W-30, API Certified) 5 Qts 4.7 Liters
4.7 Liter Engine (5W-30, API Certified) 6 Qts 5.7 Liters
5.7 Liter Engine (5W-20, API Certified) 7 Qts 6.6 Liters