From the 2006 shop manual I don't have an '04 or '05 but I would guess they are similiar - your going to need a "disconnect tool" - see figure 1 :
COOLER & LINES-OIL
DESCRIPTION
An engine oil cooler is used on all models. The cooler is a coolant-to-oil type and mounted on the right front inner
fender.
OPERATION
Engine oil travels from the oil pump and filter to the oil cooler via an oil supply line. The oil is cooled and returned
to the engine via an oil return line. Engine oil is then pumped into the main oil gallery. Engine coolant flows into the
cooler from the heater return hose and exits into the water pump inlet nipple.
STANDARD PROCEDURE - OIL COOLER LINE QUICK CONNECT FITTING
DISASSEMBLY/ASSEMBLY
DISASSEMBLY
1. Remove dust cap by pulling it straight back off of
quick connect fitting (1).
2. Place disconnect tool (4) onto oil cooler line with
the fingers of the tool facing the quick connect fitting
(1).
3. Slide disconnect tool down the line and engage the
fingers of the tool into the retaining clip. When
properly engaged in the clip, the tool will fit flush
against the quick connect fitting.
4. Rotate the disconnect tool 60° to expand the
retaining clip.
5. While holding the disconnect tool against the quick
connect fitting, pull back on the oil cooler line to
remove.
9 - 2780 ENGINE - 8.3L - SERVICE INFORMATION DR
ASSEMBLY
1. Align oil cooler line (3) with quick connect fitting (1)
while pushing straight into the fitting.
2. Push in on oil cooler line (3) until a “click” is heard
or felt.
3. Slide dust cap (4) down the oil cooler line (3) and
snap it over the quick connect fitting (1) until it is
fully seated and rotates freely. Dust cap (4) will
only snap over quick connect fitting (1) when the
cooler line (3) is properly installed.
NOTE: If dust cap will not snap into place, repeat
assembly step #2.
REMOVAL
1. Disconnect oil cooler coolant hoses (3).
2. Disconnect throttle body air inlet hose, remove air
cleaner housing assembly (Refer to 9 - ENGINE/
AIR INTAKE SYSTEM/AIR CLEANER HOUSING -
REMOVAL).
3. Drain cooling system (Refer to 7 - COOLING/ENGINE
- STANDARD PROCEDURE).
4. Using Special Tool 9005, disconnect oil supply (1)
and return lines (2) at oil cooler (Refer to 9 -
ENGINE/LUBRICATION/OIL COOLER & LINES -
STANDARD PROCEDURE).
5. Remove fasteners securing oil cooler to inner
fender and remove oil cooler.
INSTALLATION
1. Position oil cooler to mounting position.
2. Install oil cooler fasteners. Tighten to 12 N·m (105
in. lbs.).
3. Connect oil supply (1) and return lines (2) to oil
cooler and.
4. Connect oil cooler coolant hoses (3).
5. Install air cleaner housing assembly, connect throttle
body air inlet hose (Refer to 9 - ENGINE/AIR
INTAKE SYSTEM/AIR CLEANER HOUSING -
INSTALLATION).
6. Fill cooling system (Refer to 7 - COOLING/ENGINE
- STANDARD PROCEDURE).
7. Start the engine to circulate and fill the oil cooler.
Shut off the engine and check the oil level. Add oil
as needed.
8. Inspect the oil cooler connections for leaks.
diagrams below are referenced above - hope it helps: