Page 370 of 552

Towing Tips
Before setting out on a trip, practice turning, stopping
and backing the trailer in an area away from heavy
traffic.
If using a manual transmission vehicle for trailer towing,
all starts must be in FIRST gear to avoid excessive clutch
slippage.
Towing Tips — Automatic Transmission
The “D” range can be selected when towing. However, if
frequent shifting occurs while in this range, the “TOW
HAUL” or “OD/OFF” range should be selected.
NOTE:Using the “TOW HAUL” or “OD/OFF” range
while operating the vehicle under heavy operating con-
ditions will improve performance and extend transmis-
sion life by reducing excessive shifting and heat build up.
This action will also provide better engine braking.The automatic transmission fluid and filter should be
changed if you REGULARLY tow a trailer for more than
45 minutes of continuous operation. See Schedule “B” in
section 8 of this manual for transmission fluid change
intervals.
NOTE:Check the automatic transmission fluid level
before towing.
Towing Tips — Tow/Haul (If Equipped)
To reduce potential for automatic transmission overheat-
ing, turn the “TOW HAUL OD/OFF” feature ON when
driving in hilly areas or shift the transmission to Drive
position 2 on more severe grades.
370 STARTING AND OPERATING
Page 406 of 552

▫Intervention Regeneration Strategy – EVIC
Message Process Flow (Catalyst Full Message)
(6.7L Diesel Engines Only)...............434
▫Maintenance Free Batteries...............437
▫Air Conditioner Maintenance.............438
▫Power Steering — Fluid Check............439
▫Front Suspension Ball Joints..............440
▫Steering Linkage — Inspection............440
▫Front Prop Shaft Lubrication.............441
▫Front Axle Universal Drive Joints And Pivot
Bearings............................441
▫Body Lubrication.....................441
▫Windshield Wiper Blades................442
▫Windshield Washers...................442▫Exhaust System......................443
▫Cooling System.......................444
▫Fan ...............................450
▫Charge Air Cooler (Inter-Cooler)..........450
▫Hoses And Vacuum/Vapor Harnesses.......451
▫Brake System........................451
▫Clutch Linkage.......................453
▫Clutch Hydraulic System................453
▫Rear Axle And 4X4 Front Driving Axle
Fluid Level..........................454
▫Transfer Case — If Equipped.............455
▫Manual Transmission — If Equipped.......455
▫Automatic Transmission................455
406 MAINTAINING YOUR VEHICLE
Page 445 of 552

accumulation of bugs, leaves, etc. If dirty, clean by gently
spraying water from a garden hose vertically down the
face of the condenser.
Check the coolant recovery bottle tubing for brittle rub-
ber, cracking, tears, cuts and tightness of the connection
at the bottle and radiator. Inspect the entire system for
leaks.
Extremely cold ambient temperature may require the
addition of a “winter front” for effective operation of the
cab heating/cooling system. Make certain that a percent-
age of the radiator is exposed for adequate air flow
through the charge air cooler and automatic transmission
oil cooler. The percentage of opening must be increased
with the increasing ambient air temperature and/or
engine load. If the cooling fan can be heard cycling
frequently, increase the size of the opening in the winter
front.Coolant bottle level check
The coolant reserve system provides a quick visual
method of determining that the coolant level is adequate.
With the engine idling, and warmed to the normal
operating temperature, the level of the coolant on the
coolant bottle should be between the fluid level marks.
Check the coolant level whenever the hood is raised.
The radiator normally remains completely full, so there is
no longer a need to remove the coolant pressure cap
except for checking coolant freeze point or replacement
with new antifreeze coolant.
WARNING!
Never add coolant to the radiator when the engine is
overheated. Do not loosen or remove pressure cap to
cool overheated engine! The coolant is under pres-
sure and severe scalding could result.
MAINTAINING YOUR VEHICLE 445
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Page 455 of 552

Transfer Case — If Equipped
Fluid Level Check
This fluid level can be checked by removing the filler
plug. The fluid level should be to the bottom edge of the
filler plug hole with the vehicle in a level position.
Lubricant Selection
Refer to Fluids, Lubricants and Genuine Parts for the
correct lubricant type.
Manual Transmission — If Equipped
Fluid Level Check
This fluid level can be checked by removing the filler
plug. If the level of the lubricant is more than 1/4” below
the bottom of the filler hole while the vehicle is on level
ground, enough lubricant should be added to bring the
level to the bottom of the filler hole.
Lubricant Selection for 6-Speed Manual
Transmission — If Equipped
If it becomes necessary to add fluid or change the fluid,
be sure to use the same lubricant or equivalent. Refer to
Fluids, Lubricants and Genuine Parts for the correct
lubricant type.
Automatic Transmission
Fluid Level Check
The fluid level should be checked when the engine is
fully warmed up and the fluid in the transmission is at
normal operating temperature. Operation of the trans-
mission with an improper fluid level will greatly reduce
the life of the transmission and of the fluid. Check the
fluid level whenever the vehicle is serviced.
MAINTAINING YOUR VEHICLE 455
7
Page 456 of 552

Procedure For Checking Fluid Level
To properly check the automatic transmission fluid level,
the following procedure must be used:
1. The vehicle must be on level ground.
2. The engine should be running at curb idle speed for a
minimum of 60 seconds.
3. Fully apply parking brake.
4. Place the gear selector briefly in each gear position
ending with the lever in N (Neutral).
5. Remove the dipstick and determine if the fluid is hot
or warm. Hot fluid is approximately 180°F (82°C) which
is the normal operating temperature after the vehicle has
been driven at least 15 miles. The fluid can not be
comfortably held between the finger tips. Warm is when
fluid is between 85° - 125°F (29° - 52°C).6. Wipe the dipstick clean and reinsert until seated.
Remove dipstick and note reading.
a. If the fluid is hot, the reading should be in the
crosshatched area marked “OK”.
b. If the fluid is warm, the reading should be between
the two holes. If the fluid level indicates low, add
sufficient fluid to bring to the proper level.
Fluid is added through the dipstick tube.
NOTE:To prevent dirt and water from entering the
transmission after checking or replenishing fluid, make
certain that the dipstick cap is properly seated.
456 MAINTAINING YOUR VEHICLE
Page 496 of 552
Once a Month
•Check tire pressure and look for unusual wear or
damage.
•Inspect the batteries and clean and tighten the termi-
nals as required.
•Check the fluid levels of coolant reservoir, brake
master cylinder, and transmission and transfer case (if
equipped), add as needed.
•Check Filter Minder™. Replace air cleaner filter
element if necessary.
•Check all lights and all other electrical items for correct
operation.
•Drain water from the fuel filter.At Each Oil Change
•Change the engine oil filter.
•Inspect the exhaust system.
•Inspect the brake hoses.
•Inspect the U-Joints ( if equipped) and front suspen-
sion components.
•Check the automatic transmission fluid level.
•Check the manual transmission fluid level.
•Check the coolant level, hoses, and clamps.
•Lubricate outer tie rod ends.
•Lubricate Front Drive Shaft Fitting
496 MAINTENANCE SCHEDULES
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Page 505 of 552
Miles 112,500 120,000 127,500 135,000 142,500 150,000
(Kilometers) (181 000) (193 000) (205 000) (217 000) (229 000) (241 000)
Drain and refill transfer case fluid (4X4). X
Check transfer case fluid level (4X4).X
Replace fuel filter element. X X X
Inspect front wheel bearings. X X
Inspect brake linings. X X X
Inspect and adjust parking brake if necessary. X X X
Adjust valve lash clearance.X
Change 6 — speed manual transmission (G-
56) fluid.X
Drain and refill automatic transmission fluid.
Replace filter and adjust bands (48RE only)X
Inspection and service should also be performed anytime
a malfunction is observed or suspected. Retain all re-
ceipts.
SCHEDULE “B” 505
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Page 508 of 552
Miles 82,500 90,000 97,500 100,000 105,000
(Kilometers) (132 000) (144 000) (156 000) (160 000) (168 000)
[Months] [66] [72] [78] [84]
Change engine oil and engine oil filter. X X
Lubricate Front Drive Shaft Fitting (2500/3500, 4X4). X X X X
Rotate tires. X X X X
Check spare tire for proper pressure and correct stowage. X X X X
Lubricate outer tie rod ends 2500/3500 (4X4) models. X X X X
Flush and replace engine coolant, if not replaced at 60 mos. X
Check transfer case fluid level (4X4). X
Inspect drive belt, replace as required. X
Replace fuel filter element. X X
Inspect front wheel bearings. X
Inspect brake linings. X
Inspect and adjust parking brake if necessary. X
Drain and refill automatic transmission fluid. Replace filter
and adjust bands (48 RE only).X
508 SCHEDULE “A”
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