Page 298 of 406

CAUTION!
When using ERS for engine braking while descend-
ing steep grades, be careful not to overspeed the
engine. Apply the brakes as needed to prevent en-
gine overspeed.
Overdrive Operation
The automatic transmission includes an electronically
controlled Overdrive (fifth and sixth gears). The trans-
mission will automatically shift into Overdrive if the
following conditions are present:
•The shift lever is in the DRIVE position.
• The transmission fluid has reached an adequate tem-
perature.
• The engine coolant has reached an adequate tempera-
ture. •
The vehicle speed is sufficiently high.
• The driver is not heavily pressing the accelerator.
When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the TOW/HAUL switch to activate TOW/
HAUL mode. This will improve performance and reduce
the potential for transmission overheating or failure due
to excessive shifting. When operating in TOW/HAUL
mode, transmission upshifts are delayed, and the trans-
mission will automatically downshift (for engine brak-
ing) when the throttle is closed and/or during steady
braking maneuvers.
296 STARTING AND OPERATING 
         
        
        
     
        
        Page 299 of 406

The “TOW/HAUL Indicator Light” will illuminate in the
instrument cluster to indicate that TOW/HAUL mode
has been activated. Pressing the switch a second time
restores normal operation. Normal operation is always
the default at engine start-up. If TOW/HAUL mode isdesired, the switch must be pressed each time the engine
is started.
WARNING!
Do not use the “TOW/HAUL” feature when driving
in icy or slippery conditions. The increased engine
braking could cause the rear wheels to slide, and the
vehicle to swing around with the possible loss of
vehicle control, which could cause an accident possi-
bly resulting in personal injury or death.
Torque Converter Clutch
A feature designed to improve fuel economy has been
included in the automatic transmission on your vehicle.
A clutch within the torque converter engages automati-
cally at calibrated speeds. This may result in a slightly
different feeling or response during normal operation in
the upper gears. When the vehicle speed drops or during
some accelerations, the clutch automatically disengages.
TOW/HAUL Switch
5
STARTING AND OPERATING 297 
         
        
        
     
        
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NOTE:During cold weather, you may experience in-
creased effort in shifting until the transmission fluid
warms up. This is normal.
Shifting
Truck models with manual transmission are equipped
with a clutch interlocking ignition system. The clutch
pedal must be fully pressed to start the vehicle.
Fully press the clutch pedal before shifting gears. As you
release the clutch pedal, lightly press the accelerator
pedal.
This transmission has a “creeper” first gear which should
be used to start from a standing position when carrying
a payload or towing a trailer. Damage to the clutch can
result from starting in second or third gear with a loaded
vehicle. An unloaded vehicle may be launched in second
gear. Use each gear in numerical order – do not skip a
gear.
NOTE: When loaded, pulling a trailer or on a grade, the
truck should always start in first gear and not skip gears.
Shift Pattern
5
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        Page 388 of 406
Mileage or time passed (which-ever comes first):
7,500
15,000
22,500
30,000
37,500
45,000
52,500
60,000
67,500
75,000
82,500
90,000
97,500
105,000 112,500
120,000
127,500
135,000
142,500
150,000
Or Months: 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120
Or Kilometers:
12,000
24,000
36,000
48,000
60,000
72,000
84,000
96,000
108,000
120,000
132,000
144,000
156,000
168,000
180,000
192,000
204,000
216,000
228,000
240,000
Additional Maintenance
Replace engine fuel filter element. X X X X X X X X X X
Replace chassis mounted fuel
filter element. XXXXXXXX X X
Inspect the front and rear axle
surfaces. If gear oil leakage is
suspected, check the fluid level. If
using your vehicle for police, taxi,
fleet, off-road or frequent trailer
towing change the axle fluid. *
8
MAINTENANCE SCHEDULE 385 
         
        
        
     
        
        Page 389 of 406
Mileage or time passed (which-ever comes first):
7,500
15,000
22,500
30,000
37,500
45,000
52,500
60,000
67,500
75,000
82,500
90,000
97,500
105,000 112,500
120,000
127,500
135,000
142,500
150,000
Or Months: 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120
Or Kilometers:
12,000
24,000
36,000
48,000
60,000
72,000
84,000
96,000
108,000
120,000
132,000
144,000
156,000
168,000
180,000
192,000
204,000
216,000
228,000
240,000
Inspect the transfer case fluid
(4x4), change for any of the fol-
lowing: police, taxi, fleet, or fre-
quent trailer towing. XXXX X
Change the transfer case fluid
(4x4). XX
Change automatic transmission
fluid (AS69RC transmission only). XXXX X
Change the automatic transmis-
sion fluid and sump filter
(AS69RC transmission only). XX
386 MAINTENANCE SCHEDULE 
         
        
        
     
        
        Page 390 of 406
Mileage or time passed (which-ever comes first):
7,500
15,000
22,500
30,000
37,500
45,000
52,500
60,000
67,500
75,000
82,500
90,000
97,500
105,000 112,500
120,000
127,500
135,000
142,500
150,000
Or Months: 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120
Or Kilometers:
12,000
24,000
36,000
48,000
60,000
72,000
84,000
96,000
108,000
120,000
132,000
144,000
156,000
168,000
180,000
192,000
204,000
216,000
228,000
240,000
Change automatic transmission
fluid and filter(s) if using your ve-
hicle for any of the following: po-
lice, fleet, or frequent trailer tow-
ing (68RFE transmission only). XX
Change automatic transmission
fluid and filter(s). X
Change the manual transmission
fluid if using your vehicle for any
of the following: police, fleet, or
frequent trailer towing. XX
Replace Crankcase Ventilation
Filter (CCV). XX
8
MAINTENANCE SCHEDULE 387 
         
        
        
     
        
        Page 392 of 406

Inspection and service should also be performed anytime
a malfunction is observed or suspected. Retain all re-
ceipts.
* Inspect the front and rear axle surfaces every 20,000
miles (32,000 km). If gear oil leakage is suspected, check
the fluid level. If using your vehicle for police, taxi, fleet,
off-road or frequent trailer towing change the axle fluid
every 20,000 miles (32,000 km).
** Under no circumstances should oil change intervals
exceed 15,000 miles (24 000 km) or six months or 500
Hours, whichever comes first.
**** Under no circumstances should the air cleaner filter
element exceed 30,000 miles (48,000 km) or 24 months,
whichever comes first.CAUTION!
***The manufacturer highly recommends that all
cooling system service, maintenance, and repairs be
performed by your local authorized dealer.
WARNING!
•You can be badly injured working on or around a
motor vehicle. Do only service work for which you
have the knowledge and the right equipment. If
you have any doubt about your ability to perform a
service job, take your vehicle to a competent me-
chanic.
• Failure to properly inspect and maintain your ve-
hicle could result in a component malfunction and
effect vehicle handling and performance. This
could cause an accident.
8
MAINTENANCE SCHEDULE 389