Dual Tire Operation
When the vehicle is new, check the wheel nut tightness
on all wheels with a torque wrench after your first
100 miles (160 km) and then 1,000 miles (1 600 km)
after that. Whenever a wheel, wheel bolt or wheel nut is
removed or serviced, repeat the 100 miles (160 km),
and then 1,000 mile (1 600 km) wheel nut tightness
check.
SeeTightening the Wheel Nuts on page 5-86for wheel
nut tightening information and proper torque values.
{CAUTION:
If you operate your vehicle with a tire that is
badly underin ated, the tire can overheat. An
overheated tire can lose air suddenly or catch
re. You or others could be injured. Be sure all
tires (including the spare, if any) are properly
in ated.
SeeTires on page 5-82andInflation - Tire Pressure on
page 5-82for more information on proper tire inflation.
When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
influence when you need new tires.
Replace your tires when the tread depth is down to
1/8 of an inch (3.2 mm) for the front tires, or 1/16 of an
inch (1.6 mm) for a rear tire. Also, you need a new
tire if:
•You can see cord or fabric showing through the
tire’s rubber.
•The tread or sidewall is cracked, cut, or snagged
deep enough to show cord or fabric.
•The tire has a bump, bulge, or split.
•The tire has a puncture, cut, or other damage that
cannot be repaired well because of the size or
location of the damage.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire, if
your vehicle has one. Multiple conditions affect how fast
this aging takes place, including temperatures, loading
conditions, and inflation pressure maintenance. With
proper care and maintenance tires will typically wear out
before they degrade due to age. If you are unsure about
the need to replace your tires as they get older, consult
the tire manufacturer for more information.
5-84
(12)= Check steering system:
•Look for damaged, loose, or missing parts. Inspect
the steering linkage relay rod and tie rod ends for
looseness or lack of lubricant. Also look for parts
showing signs of wear or lack of lubrication. Replace
parts as needed. Also check steering gear mounting
bolts, pitman arm nut, gear housing upper cover and
side cover attaching bolts, steering column mounting
bolts and cardan joint clamp bolts; tighten if
necessary. See the service manual.
•Inspect power steering hoses, tubes, and fittings for
leaks. Hoses and lines must not be twisted, kinked,
or tightly bent. Make sure clips, clamps, supporting
tubes, and hoses are in place and properly secured.
•Check steering gear for leakage around pitman shaft
and housing. If leakage is evident (lubricant oozing
out, not just oily film), leak should be corrected
immediately.
(13)= Check front and rear suspension. Look for
damaged, loose, or missing parts or parts showing signs
of wear or lack of lubrication. Replace parts as needed.
(14)= Adjust tire pressures as indicated on the
Certification or Tire Information label for optimum tire
life. SeeTires on page 5-82for further details. Check
tires for excessive or abnormal wear or damage. Also
check for damaged wheels. Replace wheels and/or tires
as needed.(15)= Check spring-to-axle U-bolts and shackle bolts
for proper torque. See the service manual for torque
sequence and specifications. When parts are replaced,
the torque must be checked and adjusted more often
during the first 6,000 miles (10 000 km). Check torque at
500 miles (800 km) and 2,000 miles (3 000 km) after
first use of parts.
(16)= Check complete exhaust system, including DPF
pressure lines, and cab areas near the exhaust system
for broken, damaged, missing, or out-of-position parts.
Also inspect for open seams, holes, loose connections, or
other conditions which could let exhaust fumes seep into
the driver compartment. Needed repairs should be made
at once. To help maintain system integrity, replace
exhaust pipes whenever a new muffler is put on.
(17)= Check all gasoline engine drive belts for cracks,
fraying, and wear. Replace as needed.
(18)= Adjust valve lash. Incorrect valve clearance will
result in increased engine noise and reduced engine
output.
(19)= With the engine off and below normal operating
temperature, check to see that the thermostatically
controlled engine cooling fan can be rotated by hand on
viscous-operated drives. Replace as needed.
(20)= Check shields and underhood insulation for
damage or looseness. Adjust or replace as needed.
6-22
