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•Place the gearshift lever in positionP(if equipped) or neutral to aid
in engine and transmission cooling and air conditioning efficiency
during hot weather while stopped in traffic.
•Turn off the speed control. The speed control may turn off
automatically when you are towing on long, steep grades.
•Shift to a lower gear when driving down a long or steep hill. Do not
apply the brakes continuously, as they may overheat and become less
effective.
•Allow more distance for stopping with a trailer attached. Anticipate
stops and brake gradually.
FIFTH WHEEL OPERATION
WARNING:Failure to follow the fifth wheel manufacturer’s
instructions for hooking and unhooking as well as sliding the fifth
wheel could result in an accident, personal injury or death.
WARNING:When the tractor and trailer are parked unattended,
the trailer brake hand control should never be used to apply the
brake, since air may leak from the system, allowing vehicle movement,
resulting in possible property damage, personal injury or death.
Before hook-up, make sure:
•The fifth wheel jaws are fully open.
•The fifth wheel is fully tilted back to prevent body damage when the
tractor is backed under a trailer.
•You block the trailer wheels and adjust and apply the trailer spring
brakes. Never chase a trailer.
•The brake hoses and light cords are clear of the fifth wheel.
Hook-up
1. Back the tractor squarely under the trailer, engaging the fifth-wheel
jaws on the kingpin. Always back up slowly; make sure the trailer is
neither too high nor too low. Avoid backing under the trailer from an
angle.
2. Connect the service and emergency brake hoses and trailer light
connector.
3. Inspect the jaws of the fifth wheel to be sure they have fully closed
on the trailer kingpin and the trailer plate is resting securely on the
fifth wheel.
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4. Make sure the coupler release lever is in the locked position.
5. Charge the trailer brake system. Set the trailer brakes, with either
the hand valve or tractor protection valve. Pull against the trailer for
an extra check of proper hook-up. Do not pull hard enough to
damage or strain the equipment.
6. Set the tractor parking brakes and fully raise the trailer landing gear.
See theBrakeschapter for proper operation of the parking brake
and trailer brakes.
7. Check the operation of all trailer lights and correct any lights that
may be faulty.
Un-hook
1. Try to keep the tractor and trailer in a straight line.
2. Apply the parking brakes.
3. Lower the trailer landing gear, making sure it is on solid, level
ground. The weight of the trailer is to be on the landing gear.
4. Block the trailer wheels.
5. Disconnect the brake hoses and light cords. Be sure hoses and cords
are clear.
6. Pull coupler release lever to disengage the fifth wheel jaws.
7. Release the tractor parking brakes.
8. Pull out from the trailer slowly, allowing the landing gear to take the
load gradually.
WRECKER TOWING
WARNING:To reduce the risk of personal injury or property
damage when manually releasing the spring brakes, be sure to
block the wheels so the vehicle cannot move once the brakes are
released.
Note:Make sure to connect your vehicle securely to the tow vehicle and
that the tow vehicle’s parking brakes are set before releasing the disabled
vehicle’s spring brakes.
Before moving the disabled vehicle, check for adequate road clearance of
vehicle components. If possible, unload the disabled vehicle before
towing. This reduces any abnormal load to the vehicle components
resulting from the towing procedures. Before towing, make sure to
release the parking brake fully. You can reset the spring-actuated type
parking brake by recharging the air system with at least 64 psi (441 kPa)
of air. If the brake system does not retain air pressure, then you must
release the spring brakes manually. SeeParking brakein theBrakes
chapter.
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A. Side gear
B. Differential (plain) case half
C. Shift collar in the locked position
D. Actuator assembly and shift fork
E. Axle shaft
F. Interference between the shift
collar and housing
G. Shift collar in the unlocked
position
H. Outer splines: axle shaft to collar
I. Shift collar and differential case
splines
J. Inner splines: axle shaft to side
gear
Removing Axle Shafts before Towing
1. Shift the main differential to the unlocked (disengaged) position; the
differential lock light turns off.
2. Remove the cap screws and washers or stud nuts and washers from
flanges of both axle shafts.
3. Loosen the tapered dowels in the flanges of both axle shafts by
holding a 1
1 2inch diameter brass drift or hammer against the axle
shaft center and hitting it with a five or six pound hammer.Note:Do
not use a chisel or wedge to loosen the axle shafts and dowels. Use
of a chisel or wedge can damage the hub, axle shafts and oil seals.
4. Remove the tapered dowels and both axle shafts from the axle
assembly.
5. Assemble a cover over openings of both wheel ends to prevent loss of
lubricant and keep dirt away from the wheel bearing cavities.
Note:One of the axle shafts has two sets of splines. One set to engage
with the differential side gear and one set to engage with the shift collar
for the differential lock. It may be necessary to rotate the shaft slightly
to align the gear spline teeth with the shift collar teeth in order to
remove the axle shaft.
E
D
CB
A
J
IH
G
F
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BREAKING-IN
You need to break in new tires for approximately 300 miles
(480 kilometers). During this time, your vehicle may exhibit some unique
driving characteristics. Avoid driving too fast during the first 1000 miles
(1600 kilometers). Vary your speed frequently and change up through
the gears early. Do not labor the engine.
ECONOMICAL DRIVING
Several things affect your vehicle’s fuel economy, such as how you drive,
the conditions you drive under and how you maintain your vehicle.
You may improve your vehicle’s fuel economy by keeping these things in
mind:
•Accelerate and slow down in a smooth, moderate fashion.
•Drive at steady speeds without stopping.
•Anticipate stops; slowing down may eliminate the need to stop.
•Close the windows for high-speed driving.
•Drive at reasonable speeds. Traveling at 55 mph (88 km/h) uses 15%
less fuel than traveling at 65 mph (105 km/h).
•Keep the tires properly inflated and use only the recommended size.
•Use the recommended engine oil.
•Perform all regularly scheduled maintenance.
You may want to avoid doing these things since they may reduce your
vehicle’s fuel economy:
•Sudden or hard accelerations.
•Warm up your vehicle on cold mornings.
•Use the air conditioner or front defroster.
•Use the speed control in hilly terrain.
•Rest your foot on the brake pedal while driving.
•Carry unnecessary weight. Approximately 1 mpg (0.4 km/L) is lost for
every 400 pounds (180 kilograms) of weight carried).
•Add particular accessories to your vehicle (such as bug deflectors,
roll bars and light bars, running boards, ski racks).
•Drive with the wheels out of alignment.
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DRIVING THROUGH WATER
If driving through deep or standing water is unavoidable, proceed very
slowly especially if you do not know the depth. Never drive through
water that is higher than the bottom of the hubs. Traction or brake
capability may be limited and your vehicle may stall. Water may also
enter your engine’s air intake and severely damage your engine, drive
axles or the transmission (through the breather ports).
Once through the water, always dry the brakes by moving your vehicle
slowly while applying light pressure on the brake pedal. Wet brakes do
not stop the vehicle as quickly as dry brakes.
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Fuse/Relay
LocationFuse Amp
RatingProtected Circuits
103 20A Ignition switch, Passenger compartment fuse
box fuses 19, 29 and 30
104 20A Power point
105 20A Power door lock switches
106 30A Main light switch, Multi-function switch
107 50A Passenger compartment fuse box fuses 1, 2,
3, 4, 12, 13, 14 and 15
108 40A Fuel heater (diesel engine only)
20A Fuel pump module (gasoline engine only)
109 40A Power window
110 30A Windshield wiper
111 30A Body builder relay, Parking lamps
112 40A Blower motor
113 30A Heated seats, Air-Ride seat
114 — Not used
115 20A Ignition switch, Passenger compartment fuse
box fuses 8, 9, 10 and 11
116 30A Left/Right turn relays, Back up lamp relay
117 20A Stop lamps
118 60A Hydraulic brake vehicles (trailer tow package
only)
601 60A Trailer socket
602 60A Air brake trailer tow fuse block
201 — Windshield washer relay
202 — Wiper high/low relay
203 — Wiper run/park relay
204 — Windshield wiper relay
205 — Body builder relay, right turn
206 — Body builder relay, left turn
207 — ABS event relay (hydraulic brake vehicles
only)
208 — Body builder relay, back up lamps relay
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Fuse/Relay
LocationFuse Amp
RatingProtected Circuits
16 15A High beams, Indicator
17 — Not used
18 5A Dimmer switch, Interior lighting
19 15A Engine control (diesel engine only)
20 5A Starting system
21 10A DRL resistor
22 15A Air horn, Air suspension dump, Two-speed
axle, Driver-controlled locking differential
23 10A Flasher relay
24 15A Hydraulic brakes relay, Fuel heater relay
(diesel engine only), Air dryer
25 10A Blower motor relay coil
26 10A Right-hand low beam headlight
27 — Not used
28 10A Left-hand low beam headlight
29 10A Cluster, GEM
30 15A Allison electronic transmission
31 15A Mirror fold relay
Relay 1 — Interior lamps
Relay 2 — Not used
Relay 3 — Horn
Relay 4 — Not used
Relay 5 — Not used
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Relay Center
The relay center is located along the passenger side A-pillar on the right
side of the footwell.
Relay
LocationRelay Description
R1 Spring applied hydraulic release warning chime module or
PCM power VPWR 2, 3 and 4
R2 A/C compressor clutch
R3 Power windows
R4 Flasher (standard/LED)
R5 Upfitter relay 1
R6 Upfitter relay 2
R7 Headlights
R8 Cummins starter lockout
R9 Upfitter relay 3
R10 Starter
R11 DCU (diesel engine only)
R12 Two–speed axle/Differential lock
R13 Door lock
R14 Air tank moisture valve
R15 DRL #1
R16 Heated mirrors
R17 Spare
R18 Upfitter relay 4
R1
R9 R10 R11 R12 R13 R14 R15 R16 R17
R18 R19 R20 R21 R22 R23 R24 R25 R26
R2 R3 R4 R5 R6 R7 R8
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