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To check if tires are even, lay a straight edge across all
four tires. The straight edge should touch all the tires.
CAUTION!4500/5500 Dual Rear Tires have only one approved
direction of rotation. This is to accommodate the
asymmetrical design (tread pattern) of the On/Off
road tire.
• When replacing a flat, the spare tire may have to
be remounted on the rim or installed at a different
location to maintain the correct placement of the
tire on the wheel relative to the tire/wheel position
on the vehicle. For example, if the spare is used to
replace an outer rear tire it will have to be re-
mounted on the rim so that the wheel is dished
inward. That way the tread design of asymmetrical
tires will maintain proper position. FUEL REQUIREMENTS
The 5.7L engine is designed to meet all
emissions regulations and provide satisfac-
tory fuel economy and performance when
using high-quality unleaded gasoline hav-
ing an octane range of 87 to 89. The manu-
facturer recommends the use of 89 octane
for optimum performance. The use of premium gasoline
is not recommended, as it will not provide any benefit
over regular gasoline in these engines.
Light spark knock at low engine speeds is not harmful to
your engine. However, continued heavy spark knock at
high speeds can cause damage and immediate service is
required.
Poor quality gasoline can cause problems such as hard
starting, stalling and hesitations. If you experience these
symptoms, try another brand of “regular” gasoline be-
fore considering service for the vehicle.
5 STARTING AND OPERATING 317
Page 365 of 472

Slots in the wheels will assist in properly orienting the
inner and outer wheels. Align these slots when assem-
bling the wheels for best access to the tire valve on the
inner wheel. The tires of both dual wheels must be
completely off the ground when tightening to insure
wheel centering and maximum wheel clamping.
Dual wheel models require a special heavy-duty lug nut
tightening adapter (included with the vehicle) to cor-
rectly tighten the lug nuts. Also, when it is necessary to
remove and install dual rear wheels, use a proper vehicle
lifting device.
NOTE: When installing a spare tire (if equipped) as part
of a dual rear wheel end combination, the tire diameter of
the two individual tires must be compared. If there is a
significant difference, the larger tire should be installed in
a front location. The correct direction of rotation for dual
tire installations must also be observed. These dual rear wheels should be tightened as follows:
Tightening Pattern (8 Studs)364 WHAT TO DO IN EMERGENCIES
Page 367 of 472

Disc Wheels Type Nut Stud Size Torque Ft Lbs Torque Newton Meters
Cone 9/16-18 120-150 160-200
Flanged 9/16-18 130-160 190-220
To Stow The Flat Or Spare — If Equipped
Refer to Upfitters Body Builders Guide for information
on stowing your spare tire (if equipped).
HOISTING
A conventional floor jack may be used at the jacking
locations. Refer to the graphics that show jacking loca-
tions. However, a floor jack or frame hoist must never be
used on any other parts or the underbody.
CAUTION!Never use a floor jack directly under the differential
housing of a loaded truck or damage to your vehicle
may result. JUMP-STARTING PROCEDURES
If your vehicle has a discharged battery it can be jump-
started using a set of jumper cables and a battery in
another vehicle or by using a portable battery booster
pack. Jump-starting can be dangerous if done improperly
so please follow the procedures in this section carefully.
NOTE: When using a portable battery booster pack
follow the manufacturer ’s operating instructions and
precautions.366 WHAT TO DO IN EMERGENCIES