Page 280 of 430

To reset the Engine Oil Life System, do the
following:
1. Turn the ignition key to RUN with the
engine off.
2. Fully apply and hold the brake pedal while
you fully press and release the accelerator
pedal, pausing slightly at each press and each
release, three times within five seconds.
3. Turn the key to OFF.
If the change engine oil light comes back on when
you start your vehicle, the Engine Oil Life
System has not reset. Repeat the procedure.
Engine Air Cleaner/Filter
The engine air
cleaner/filter is located
in the center of the
engine compartment.
When to Inspect the Engine Air
Cleaner/Filter
If your vehicle has an
air cleaner/filter change
indicator, inspect the
indicator at every
oil change and replace
the filter when the
indicator tells you to.
For vehicles without a change indicator, inspect
the air cleaner/filter at every oil change and
replace the filter at the first oil change after
25,000 miles (40 000 km).
How to Inspect the Engine Air
Cleaner/Filter
Locate the filter change indicator. When the
change indicator turns black or is in the red/orange
change area, replace the filter and reset the
indicator.
280
Page 282 of 430

3. Store the seal in the inlet, located on the
underside of the hood
4. Store the clamp on the coolant surge tank.
Pull the overflow tube out of the white
plastic retainer, slip the clamp over and
reinstall the hose.
The seal will need to be replaced on to the air
cleaner for normal driving, especially in the
warmer months.
Automatic Transmission Fluid
When to Check
A good time to check your automatic transmission
fluid level is when the engine oil is checked.
See your Allison Automatic Transmission
Operator’s Manual to find out when to change
your transmission fluid and filters.
How to Check and What to Use
The Allison Automatic Transmission Operator’s
Manual that came with the vehicle shows how to
check the automatic transmission fluid and
what fluid to use.
Automatic Transmission External Filter
Your automatic transmission filter requires
periodic replacement.
Consult the Allison Automatic Transmission
Operator’s Manual that came with the vehicle for
proper change intervals.
282
Page 283 of 430

Manual Transmission Fluid
When to Check
A good time to have it checked is when the
engine oil is checked. Refer to the Maintenance
Schedule to find out when to check and change
your manual transmission fluid. SeeScheduled
Maintenance on page 363.
How to Check and What to Use
Check the fluid level only when your engine is off,
the vehicle is parked on a level place, and the
transmission is cool enough for you to rest
your fingers on the transmission case.
To check the transmission fluid level, do the
following:
1. Remove the filler plug.
2. Check to be sure that the lubricant level is up
to the bottom of the fill opening. On heavy
duty transmissions, an inch of oil level equals
about one gallon of fluid.3. If the fluid level is good, reinstall the plug and
be sure it is fully seated. If the fluid level is
low, add more fluid as described in the
next steps. Refer to the Maintenance
Schedule to determine what kind of fluid to
use. SeePart C: Recommended Fluids
and Lubricants on page 397.
How to Add Fluid
To add transmission fluid, do the following:
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only
enough fluid to bring the fluid level up to
the bottom of the fill opening. Refer to
the Maintenance Schedule to determine the
proper fluid to use. SeePart C:
Recommended Fluids and Lubricants on
page 397.
3. Reinstall the filler plug. Be sure the plug is
fully seated.
283
Page 284 of 430

Engine Coolant (Gas and
DURAMAX
®/Isuzu Engines)
The cooling system in your vehicle is filled with
DEX-COOL®engine coolant. This coolant is
designed to remain in your vehicle for five years or
150,000 miles (240 000 km), whichever occurs
first, if you add only DEX-COOL
®extended
life coolant.
The following explains your cooling system and
how to add coolant when it is low. If you have
a problem with engine overheating, seeEngine
Overheating on page 288.A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
•Give freezing protection down to
−34°F (−37°C).
•Give boiling protection up to 265°F (129°C).
•Protect against rust and corrosion.
•Help keep the proper engine temperature.
•Let the warning lights and gages work as
they should.
Notice:Using coolant other than
DEX-COOL
®may cause premature engine,
heater core or radiator corrosion. In addition,
the engine coolant may require changing
sooner, at 30,000 miles (50 000 km) or
24 months, whichever occurs rst. Any
repairs would not be covered by your
warranty. Always use DEX-COOL
®
(silicate-free) coolant in your vehicle.
284
Page 285 of 430

What to Use
Use a mixture of one-half clean, drinkable water
and one-half DEX-COOL®coolant which will
not damage aluminum parts. If you use this coolant
mixture, you do not need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can
boil before the proper coolant mixture will.
Your vehicle’s coolant warning system is
set for the proper coolant mixture. With
plain water or the wrong mixture, your
engine could get too hot but you would
not get the overheat warning. Your engine
could catch re and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.Notice:If you use an improper coolant
mixture, your engine could overheat and be
badly damaged. The repair cost would not be
covered by your warranty. Too much water
in the mixture can freeze and crack the engine,
radiator, heater core, and other parts.
If you have to add coolant more than four times a
year, have your dealer check your cooling system.
Notice:If you use extra inhibitors and/or
additives in your vehicle’s cooling system, you
could damage your vehicle. Use only the
proper mixture of the engine coolant listed in
this manual for the cooling system. See
Part C: Recommended Fluids and Lubricants
on page 397for more information.
285
Page 290 of 430
Cooling System (Gas and
DURAMAX
®/Isuzu Engines)
When you decide it is safe to lift the hood, here is
what you will see:
A. Engine Fan
B. Coolant Surge TankIf your vehicle has a Caterpillar
®diesel engine,
see the Caterpillar®Diesel Engine Operation and
Maintenance Manual provided with your vehicle.
If the coolant inside the coolant surge tank is
boiling, do not do anything else until it cools down.
The vehicle should be parked on a level surface.
The coolant level should
be at the FULL COLD
mark or higher. If it is
not, you may have a leak
at the pressure cap or in
the radiator hoses,
heater hoses, radiator,
water pump, or
somewhere else in the
cooling system.
290
Page 292 of 430

If no coolant is visible in the surge tank, add
coolant as follows:
{CAUTION:
Steam and scalding liquids from a hot
cooling system can blow out and burn
you badly. They are under pressure, and if
you turn the coolant surge tank pressure
cap — even a little — they can come out at
high speed. Never turn the cap when the
cooling system, including the coolant
surge tank pressure cap, is hot. Wait for
the cooling system and coolant surge
tank pressure cap to cool if you ever have
to turn the pressure cap.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can
boil before the proper coolant mixture will.
Your vehicle’s coolant warning system is
set for the proper coolant mixture. With
plain water or the wrong mixture, your
engine could get too hot but you would
not get the overheat warning. Your engine
could catch re and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
Notice:In cold weather, water can freeze and
crack the engine, radiator, heater core and
other parts. Use the recommended coolant and
the proper coolant mixture.
292
Page 298 of 430

What to Add
Use the proper fluid listed in the Maintenance
Schedule. Use new brake fluid from a sealed
container only.
Always clean the brake fluid reservoir cap/cover
and the area around the cap/cover before
removing it. This will help keep dirt from entering
the reservoir.
{CAUTION:
With the wrong kind of uid in the brake
system, the brakes may not work well, or
they may not even work at all. This could
cause a crash. Always use the proper
brake uid.Notice:
Using the wrong uid can badly damage
brake system parts. For example, just a few
drops of mineral-based oil, such as engine
oil, in the brake system can damage brake
system parts so badly that they will have to
be replaced. Do not let someone put in the
wrong kind of uid, and do not use DOT-5
silicone brake uid.
If you spill brake uid on your vehicle’s
painted surfaces, the paint nish can be
damaged. Be careful not to spill brake uid
on your vehicle. If you do, wash it off
immediately. SeeWashing Your Vehicle on
page 335.
298