2001 DODGE RAM check engine light

VECI LABEL
DESCRIPTION
Vehicles equipped with 3.9L V-6 or 5.2L/5.9L V-8
LDC-gas powered engines have a VECI label.
The label combines both emission control informa-
tion and vacuum hose routing. This label is located
in the engine compartment in front of the radiator
(Fig. 2).
The VECI label contains the following:
²Engine family and displacement
²Evaporative family
²Emission control system schematic
²Certification application
²Engine timing specifications (if adjustable)
²Idle speeds (if adjustable)
²Spark plug and gap
The 5.9L HDC-gas powered engine will have two
labels. One of the labels is located in front of the
radiator in the engine compartment (Fig. 2) and will
contain vacuum hose routing only. The other is
attached to the drivers side of the engine air cleaner
housing (Fig. 2).
The VECI label for the 5.9L HDC-gas powered
engine will contain the following:
²Engine family and displacement
²Evaporative family
²Certification application
²Engine timing specifications (if adjustable)
²Idle speeds (if adjustable)
²Spark plug and gap
The label for the 8.0L V-10 HDC-gas powered
engine is also located in the engine compartment. Itis attached to a riveted metal plate located to the
right side of the generator (Fig. 3).
OPERATION
There are unique VECI labels for vehicles built for
sale in the country of Canada and for both Light
Duty Cycle (LDC) and Heavy Duty Cycle (HDC)
engines. Canadian labels are written in both the
English and French languages. For all Canadian
vehicles, the label is split into two different labels.
The VECI labels are permanently attached and
cannot be removed without defacing information and
destroying label.
VEHICLE IDENTIFICATION
NUMBER
DESCRIPTION
VIN CODING/LOCATIONS
The Vehicle Identification Number (VIN) plate is
located on the lower windshield fence near the left
A-pillar (Fig. 4). The VIN contains 17 characters that
provide data concerning the vehicle. Refer to the VIN
decoding chart to determine the identification of a
vehicle.
The Vehicle Identification Number is also
imprinted on the:
²Body Code Plate.
²Equipment Identification Plate.
²Vehicle Safety Certification Label.
²Frame rail.
To protect the consumer from theft and possible
fraud the manufacturer is required to include a
Check Digit at the ninth position of the Vehicle Iden-
Fig. 2 VECI Label Location
1 - VEHICLE EMISSION CONTROL INFORMATION (VECI) LABEL
2 - VECI LABEL (5.9L HDC FOR CANADA ONLY)
3 - VECI LABEL (5.9L HDC ONLY) (INCLUDES CANADA)
Fig. 3 VECI Label LocationÐ8.0L V-10 Engine
1 - VECI LABEL
2 - GENERATOR
10 INTRODUCTIONBR/BE

It is even more important to look for gasoline with-
out MMT in Canada because MMT can be used at
levels higher than allowed in the United States.
MMT is prohibited in Federal and California refor-
mulated gasoline.
SULFUR IN GASOLINE
If you live in the northeast United States, your
vehicle may have been designed to meet California
low emission standards with Cleaner-Burning Cali-
fornia reformulated gasoline with low sulfur. If such
fuels are not available in states adopting California
emission standards, your vehicles will operate satis-
factorily on fuels meeting federal specifications, but
emission control system performance may be
adversely affected. Gasoline sold outside of California
is permitted to have higher sulfur levels which may
affect the performance of the vehicle's catalytic con-
verter. This may cause the Malfunction Indicator
Lamp (MIL), Check Engine or Service Engine Soon
light to illuminate. We recommend that you try a dif-
ferent brand of unleaded gasoline having lower sulfur
to determine if the problem is fuel related prior to
returning your vehicle to an authorized dealer for
service.
CAUTION: If the Malfunction Indicator Lamp (MIL),
Check Engine or Service Engine Soon light is flash-
ing, immediate service is required; see on-board
diagnostics system section.
MATERIALS ADDED TO FUEL
All gasoline sold in the United States and Canada
are required to contain effective detergent additives.
Use of additional detergents or other additives is not
needed under normal conditions.
FUEL SYSTEM CAUTIONS
CAUTION: Follow these guidelines to maintain your
vehicle's performance:
²The use of leaded gas is prohibited by Federal
law. Using leaded gasoline can impair engine perfor-
mance, damage the emission control system, and
could result in loss of warranty coverage.
²An out-of-tune engine, or certain fuel or ignition
malfunctions, can cause the catalytic converter to
overheat. If you notice a pungent burning odor or
some light smoke, your engine may be out of tune or
malfunctioning and may require immediate service.
Contact your dealer for service assistance.²When pulling a heavy load or driving a fully
loaded vehicle when the humidity is low and the tem-
perature is high, use a premium unleaded fuel to
help prevent spark knock. If spark knock persists,
lighten the load, or engine piston damage may result.
²The use of fuel additives which are now being
sold as octane enhancers is not recommended. Most
of these products contain high concentrations of
methanol. Fuel system damage or vehicle perfor-
mance problems resulting from the use of such fuels
or additives is not the responsibility of Daimler-
Chrysler Corporation and may not be covered under
the new vehicle warranty.
NOTE: Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
DESCRIPTION - FUEL REQUIREMENTS -
DIESEL ENGINE
DESCRIPTION
WARNING: Do not use alcohol or gasoline as a fuel
blending agent. They can be unstable under certain
conditions and hazardous or explosive when mixed
with diesel fuel.
Use good quality diesel fuel from a reputable sup-
plier in your Dodge truck. For most year-round ser-
vice, number 2 diesel fuel meeting ASTM
specification D-975 will provide good performance. If
the vehicle is exposed to extreme cold (below 0ÉF/-
18ÉC), or is required to operate at colder-than-normal
conditions for prolonged periods, use climatized No. 2
diesel fuel or dilute the No. 2 diesel fuel with 50%
No. 1 diesel fuel. This will provide better protection
from fuel gelling or wax-plugging of the fuel filters.
Diesel fuel is seldom completely free of water. To
prevent fuel system trouble, including fuel line freez-
ing in winter, drain the accumulated water from the
fuel/water separator using the fuel/water separator
drain provided. If you buy good-quality fuel and fol-
low the cold-weather advice above, fuel conditioners
should not be required in your vehicle. If available in
your area, a high cetane ªpremiumº diesel fuel may
offer improved cold starting and warm-up perfor-
mance.
0 - 2 LUBRICATION & MAINTENANCEBR/BE
LUBRICATION & MAINTENANCE (Continued)

MAINTENANCE SCHEDULES
LIGHT DUTY ENGINE (1500 AND 2500
MODELS EXCEPT 8.0L) MAINTENANCE
SCHEDULES
There are two maintenance schedules that show
proper service for the vehicle.
First is ScheduleªAº. It lists all the scheduled
maintenance to be performed under ªnormalº operat-
ing conditions.
Second is ScheduleªBºIt is a schedule for vehicles
that are operated under the conditions listed at the
beginning of that schedule.
Use the schedule that best describes the driving
conditions.
Where time and mileage are listed, follow the
interval that occurs first.
At Each Stop For Fuel
²Check engine oil level and add as required.
²Check windshield washer solvent and add as
required.
²Clean windshield and wiper blades as required.
Once A Month
²Check tire pressure and look for unusual wear
or damage.
²Inspect battery and clean and tighten terminals
as required.
²Check fluid levels of coolant reservoir, brake
master cylinder, power steering, and transmission
and add as needed.
²Check all lights and all other electrical items for
correct operation.
²Inspect and clean wiper blades. Replace if
required.
At Each Oil Change
²Inspect exhaust system.
²Inspect brake hoses.
²Adjust rear brake shoe to drum clearance.
²Rotate the tires at each oil change interval
shown on schedule ªAº (7,500 Miles) or every other
interval shown on schedule ªBº (6,000 Miles).
²Check engine coolant level, hoses, and clamps.
²Lubricate steering linkage.
EMISSION CONTROL SYSTEM MAINTENANCE
The scheduled emission maintenance listed inbold
typeon the Maintenance Schedules, must be done at
the mileage specified to assure the continued proper
functioning of the emission control system. These,
and all other maintenance services included in this
manual, should be done to provide the best vehicle
performance and reliability. More frequent mainte-
nance may be needed for vehicles in severe operatingconditions such as dusty areas and very short trip
driving.
FLUID FILL LOCATIONS AND LUBRICATION
POINTS
The fluid check/fill locations and lubrication points
are located in each applicable group.
LIGHT DUTY SCHEDULE ªAº
7,500 Miles (12 000 km) or at 6 months
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
15,000 Miles (24 000 km) or at 12 months
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
22,500 Miles (36 000 km) or at 18 months
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Inspect brake linings.
²Inspect front wheel bearings. Clean and repack,
if required (4x2).
²Lubricate the steering linkages.
²Lubricate non permanently sealed ball joints.
²Check manual transmission fluid level.
²Inspect exhaust system.
30,000 Miles (48 000 km) or at 24 months
²Replace engine air cleaner element.
²Replace spark plugs.
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Inspect manual transmission fluid level.
²Inspect exhaust system.
37,500 Miles (60 000 km) or at 30 months
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
BR/BELUBRICATION & MAINTENANCE 0 - 7

105,000 Miles (168 000 km) or at 84 months
²Inspect auto tension drive belt and replace if
required.**
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
112,500 Miles (180 000 km) or at 90 months
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Flush and replace engine coolant if it has been
30,000 miles (48 000 km) or 24 months since last
change.
²Inspect brake hoses.
²Inspect brake linings.
²Inspect front wheel bearings. Clean and repack,
if required (4x2).
²Lubricate the steering linkages.
²Lubricate non permanently sealed ball joints.
²Check manual transmission fluid level.
²Drain and refill transfer case fluid.
²Inspect exhaust system.
120,000 Miles (192 000 km) or at 96 months
²Replace engine air cleaner element.
²Replace ignition cables.
²Check PCV valve and replace as neces-
sary.*
²Replace spark plugs.
²Inspect auto tension drive belt and replace if
required.**
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
*This maintenance is recommended by Daimler-
Chrysler to the customer but it is not required to
maintain warranty on the PCV valve.
**This maintenance is not required if the belt was
previously replaced.
LIGHT DUTY SCHEDULE ªBº
Follow this schedule if the vehicle is usually oper-
ated under one or more of the following conditions.
²Frequent short trips of less than 5 miles.
²Frequent driving in dusty conditions.
²Trailer towing.
²Frequent long periods of engine idling.²More than 50 percent of the driving is at sus-
tained high speeds during hot weather, above 90ÉF
(32ÉC).
²Frequent stop and go driving.
²Day and night temperatures are below freezing.
²Taxi, police or delivery service (commercial ser-
vice).
²Off-road or desert operation.
3,000 Miles (5 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
6,000 Miles (10 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
9,000 Miles (14 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
12,000 Miles (19 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Inspect brake linings.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Change rear axle fluid.
²Change front axle fluid (4x4).
²Inspect exhaust system.
15,000 Miles (24 000 km)
²Inspect engine air cleaner element, replace
as necessary.
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
BR/BELUBRICATION & MAINTENANCE 0 - 9
MAINTENANCE SCHEDULES (Continued)

²Change front axle fluid (4x4).
²Inspect exhaust system.
111,000 Miles (178 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Flush and replace engine coolant.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
114,000 Miles (182 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
117,000 Miles (187 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Lubricate the steering linkages.
²Check manual transmission fluid level.
²Inspect exhaust system.
120,000 Miles (192 000 km)
²Replace engine air cleaner element.
²Replace ignition cables.
²
Inspect PCV valve and replace as necessary.*
²Replace spark plugs.
²Inspect auto tension drive belt and replace if
required.**
²Change engine oil.
²Replace engine oil filter.
²Inspect engine coolant level, hoses, and clamps.
²Inspect brake hoses.
²Inspect brake linings.
²Lubricate the steering linkages.
²Change automatic transmission fluid, filter and
adjust the bands.
²Check manual transmission fluid level.
²Change rear axle fluid.
²Change front axle fluid (4x4).
²Inspect exhaust system.
*This maintenance is recommended by Daimler-
Chrysler to the customer but it is not required to
maintain warranty on the PCV valve.
**This maintenance is not required if the belt was
previously replaced.
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
DESCRIPTION - MEDIUM DUTY TRUCK
MAINTENANCE SCHEDULE (8.0L 2500 & 3500
MODELS Ð CALIFORNIA ONLY)
There are two maintenance schedules that show
proper service based on the conditions that the vehi-
cle is subjected to. Use the schedule that best
describes these conditions.
ScheduleªAº, lists all the scheduled maintenance
to be performed under normal operating conditions
for Medium Duty vehicles.
ScheduleªBº, lists maintenance recommended for
Medium Duty vehicles operated under the conditions
listed at the beginning of that schedule.
²Where the time and mileage are listed, follow
the interval that occurs first.
At Each Stop For Fuel
²Check engine oil level and add as required.
²Check windshield washer solvent and add as
required.
²Clean windshield and wiper blades as required.
Once A Month
²Check tire pressure and look for unusual wear
or damage.
²Inspect battery and clean and tighten terminals
as required.
²Check fluid levels of coolant reservoir, brake
master cylinder, power steering, and transmission
and add as needed.
²Check all lights and all other electrical items for
correct operation.
²
Inspect and clean wiper blades. Replace if required.
At Each Oil Change
²Inspect exhaust system.
²Inspect brake hoses.
²Adjust rear brakes.
²Rotate the tires at each oil change interval
shown on schedule ªAº (6,000 Miles) or every other
interval shown on schedule ªBº (6,000 Miles)
²Check engine coolant level, hoses and clamps.
²Lubricate steering linkage.
EMISSION CONTROL SYSTEM MAINTENANCE
The scheduled emission maintenance listed inbold
typeon the Maintenance Schedules, must be done at
the mileage specified to assure the continued proper
functioning of the emission control system. These,
and all other maintenance services included in this
manual, should be done to provide the best vehicle
performance and reliability. More frequent mainte-
nance may be needed for vehicles in severe operating
conditions such as dusty areas and very short trip
driving.
BR/BELUBRICATION & MAINTENANCE 0 - 13
MAINTENANCE SCHEDULES (Continued)

²Inspect brake linings.
³Off-the-highway operation, trailer towing snow
plowing, prolonged operation with heavy loading,
especially in hot weather require the more frequent
transmission service indicated with an ³ in Schedule
ªBº. Perform these services if the vehicle is usually
operated under these conditions.
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
DESCRIPTION - HEAVY DUTY ENGINE
(FEDERAL ONLY ± 2500 8.0L HD AND 3500
5.9L& 8.0L MODELS) MAINTENANCE
SCHEDULES
There are two maintenance schedules that show
proper service based on the conditions that the vehi-
cle is subjected to. Use the schedule that best
describes these conditions.
ScheduleªAº, lists all the scheduled maintenance
to be performed under normal operating conditions
for Heavy Duty vehicles.
ScheduleªBº, lists maintenance recommended for
Heavy Duty vehicles operated under the conditions
listed at the beginning of that schedule.
²Where time and mileage are listed, follow the
interval that occurs first.
At Each Stop For Fuel
²Check engine oil level, add as required.
²Check windshield washer solvent and add if
required.
²Clean windshield and wiper blades as required.
Once A Month
²Check tire pressure and look for unusual wear
or damage.
²Inspect battery and clean and tighten terminals
as required.
²Check fluid levels of coolant reservoir, power
steering and transmission and add as needed.
²Check all lights and all other electrical items for
correct operation.
²Inspect and clean wiper blades. Replace if
required.
At Each Oil Change
²Inspect exhaust system.
²Inspect brake hoses.
²Adjust rear brakes.
²Rotate the tires at each oil change interval
shown on schedule ªAº (6,000 Miles) or every other
interval shown on schedule ªBº (6,000 Miles).
²Check engine coolant level, hoses, and clamps.
²Lubricate steering linkage.
EMISSION CONTROL SYSTEM MAINTENANCE
The scheduled emission maintenance listed inbold
typeon the Maintenance Schedules, must be done at
the mileage specified to assure the continued proper
functioning of the emission control system. These,
and all other maintenance services included in this
manual, should be done to provide the best vehicle
performance and reliability. More frequent mainte-
nance may be needed for vehicles in severe operating
conditions such as dusty areas and very short trip
driving.
FLUID FILL LOCATIONS AND LUBRICATION
POINTS
The fluid fill/check locations and lubrication points
are located in each applicable group.
HEAVY DUTY SCHEDULE ªAº
6,000 miles (10 000 km) or at 6 months
²Change engine oil.
²Replace engine oil filter.
12,000 Miles (19 000 km) or at 12 months
²Change engine oil.
²Replace engine oil filter.
²Inspect engine air cleaner element, replace
as necessary (8.0L only).
18,000 Miles (29 000 km) or at 18 months
²Change engine oil.
²Replace engine oil filter.
²Inspect brake linings
²Inspect front wheel bearings. Clean and repack,
if required (4x4).
24,000 Miles (38 000 km) or at 24 months
²Change engine oil.
²Replace engine oil filter.
²Replace engine air cleaner element and air
pump filter.
²Clean and lubricate crankcase inlet air filter
(5.9L).
²Drain and refill automatic transmission fluid.
Replace filter and adjust bands.
²Inspect front wheel bearings. Clean and repack,
if required (4x2).
30,000 Miles (48 000 km) or at 30 months
²Change engine oil.
²Replace engine oil filter.
²Replace spark plugs.
36,000 Miles (58 000 km) or at 36 months
²Change engine oil.
²Replace engine oil filter.
BR/BELUBRICATION & MAINTENANCE 0 - 17
MAINTENANCE SCHEDULES (Continued)

99,000 Miles (156 000 km)
²Change engine oil.
²Replace engine oil filter.
²Lubricate tie rod ends every 3,000 miles (5 000
km).
²Inspect front wheel bearings (4x2).
102,000 Miles (163 000 km)
²Change engine oil.
²Replace engine oil filter.
²Lubricate tie rod ends every 3,000 miles (5 000
km).
²Inspect front wheel bearings (4x4).
105,000 Miles (168 000 km)
²Change engine oil.
²Replace engine oil filter.
²Lubricate tie rod ends every 3,000 miles (5 000
km).
108,000 Miles (173 000 km)
²Change engine oil.
²Replace engine oil filter.
²Inspect engine air cleaner element and air
pump filter, replace as necessary.
²Drain and refill automatic transmission fluid.
Replace filter and adjust bands.³
²Drain and refill transfer case fluid (4x4).
²Change rear axle fluid.
²Change front axle fluid (4x4).
²Inspect brake linings.
²Flush and replace engine coolant if it has been
30,000 miles (48 000 km) since last change.
²Lubricate tie rod ends every 3,000 miles (5 000
km).
²Inspect front wheel bearings (4x4).
²Inspect front wheel bearings (4x2).
*Requires Service Reminder Indicator Light. If so
equipped, these parts are to be replaced at the indi-
cated mileage or when the service reminder indicator
light remains on continuously with the key in the
ªONº position, whichever occurs first.
³Off-the-highway operation, trailer towing, snow
plowing, prolonged operation with heavy loading,
especially in hot weather require the more frequent
transmission service indicated witha³inSchedule
ªBº. Perform these services if you usually operate
your Ram Truck under these conditions.
Inspection and service should also be performed
anytime a malfunction is observed or suspected.
DESCRIPTION - MAINTENANCE SCHEDULES
Ð 24±VALVE CUMMINS TURBO DIESEL
There are two maintenance schedules that show
proper service for the vehicle.First is ScheduleªA.ºIt lists all the scheduled
maintenance to be performed under ªnormalº operat-
ing conditions.
Second is ScheduleªB.ºIt is a schedule for vehicles
that are operated under the conditions listed at the
beginning of that schedule.
Use the schedule that best describes the driving
conditions.
Where time and mileage are listed, follow the
interval that occurs first.
At Each Stop For Fuel
²Check engine oil level and add as required.
²Check windshield washer solvent and add if
required.
²Clean windshield and wiper blades as required.
²Drain water from fuel filter.
Once A Month
²Check tire pressure and look for unusual wear
or damage.
²Inspect battery and clean and tighten terminals
as required.
²Check fluid levels of coolant reservoir, brake
master cylinder, power steering, and transmission.
Add fluid as required.
²Check all lights and all other electrical items for
correct operation.
²Check Filter Mindery. Replace air cleaner
element if necessary.
²Inspect and clean wiper blades. Replace if
required.
At Each Oil Change
²Inspect exhaust system.
²Inspect brake hoses.
²Adjust rear brakes.
²Rotate the tires at each oil change interval
shown at 7, 5000 miles (12 000 km) on schedule ªAº
or every other interval shown at 7,500 miles (12 000
km) on schedule ªBº.
²Check engine coolant level, hoses, and clamps.
²Lubricate steering linkage.
²Drain crankcase breather canister (if equipped).
EMISSION CONTROL SYSTEM MAINTENANCE
The scheduled emission maintenance listed inbold
typeon the Maintenance Schedules, must be done at
the mileage specified to assure the continued proper
functioning of the emission control system. These,
and all other maintenance services included in this
manual, should be done to provide the best vehicle
performance and reliability. More frequent mainte-
nance may be needed for vehicles in severe operating
conditions such as dusty areas and very short trip
driving.
0 - 22 LUBRICATION & MAINTENANCEBR/BE
MAINTENANCE SCHEDULES (Continued)

cle turns. A worn pinion mate shaft can also cause a
snapping or a knocking noise.
BEARING NOISE
The axle shaft, differential and pinion bearings can
all produce noise when worn or damaged. Bearing
noise can be either a whining, or a growling sound.
Pinion bearings have a constant-pitch noise. This
noise changes only with vehicle speed. Pinion bearing
noise will be higher pitched because it rotates at a
faster rate. Drive the vehicle and load the differen-
tial. If bearing noise occurs, the rear pinion bearing
is the source of the noise. If the bearing noise is
heard during a coast, the front pinion bearing is the
source.
Worn or damaged differential bearings usually pro-
duce a low pitch noise. Differential bearing noise is
similar to pinion bearing noise. The pitch of differen-
tial bearing noise is also constant and varies only
with vehicle speed.
Axle shaft bearings produce noise and vibration
when worn or damaged. The noise generally changes
when the bearings are loaded. Road test the vehicle.
Turn the vehicle sharply to the left and to the right.
This will load the bearings and change the noise
level. Where axle bearing damage is slight, the noise
is usually not noticeable at speeds above 30 mph.
LOW SPEED KNOCK
Low speed knock is generally caused by a worn
U-joint or by worn side-gear thrust washers. A worn
pinion shaft bore will also cause low speed knock.
VIBRATION
Vibration at the rear of the vehicle is usually
caused by:
²Damaged drive shaft.²Missing drive shaft balance weight(s).
²Worn or out of balance wheels.
²Loose wheel lug nuts.
²Worn U-joint(s).
²Loose/broken springs.
²Damaged axle shaft bearing(s).
²Loose pinion gear nut.
²Excessive pinion yoke run out.
²Bent axle shaft(s).
Check for loose or damaged front end components
or engine/transmission mounts. These components
can contribute to what appears to be a rear end
vibration. Do not overlook engine accessories, brack-
ets and drive belts.
All driveline components should be examined
before starting any repair.
(Refer to 22 - TIRES/WHEELS - DIAGNOSIS AND
TESTING)
DRIVELINE SNAP
A snap or clunk noise when the vehicle is shifted
into gear (or the clutch engaged) can be caused by:
²High engine idle speed.
²Transmission shift operation.
²Loose engine/transmission/transfer case mounts.
²Worn U-joints.
²Loose spring mounts.
²Loose pinion gear nut and yoke.
²Excessive ring gear backlash.
²Excessive side gear to case clearance.
The source of a snap or a clunk noise can be deter-
mined with the assistance of a helper. Raise the vehi-
cle on a hoist with the wheels free to rotate. Instruct
the helper to shift the transmission into gear. Listen
for the noise, a mechanics stethoscope is helpful in
isolating the source of a noise.
3 - 14 FRONT AXLE - 216FBIBR/BE
FRONT AXLE - 216FBI (Continued)