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Rear Suspended Tow
When the vehicle is being recovered by rear suspended tow:
The ignition key must be removed from the ignition switch to lock the steering.
The rear wheels must be correctly positioned in the lifting cradle and securely tied down.
Emergency Towing
WARNING: If the engine is not running, the steering will become heavy and the force necessary to effectively apply the
brakes will be greatly increased.
CAUTION: A vehicle with a defective transmission must be towed by rear suspended tow.
When the vehicle is being towed on its own wheels:
Local regulations for the towing of vehicles must be followed. In some countries the registration number of the towing
vehicle and an 'On Tow' sign or warning triangle must be displayed at the rear of the towed vehicle.
The gear selector lever must be in Neutral.
The ignition switch must be in position II to release the steering lock and make the direction indicators, horn and stop
lamps operate.
A distance of 0,8 km (0.5 mile) must not be exceeded.
A speed of 48 km/h (30 mph) must not be exceeded.
The tow rope must be attached to the front towing eye. www.JagDocs.com
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Published: 11-May-2011
Noise, Vibration and Harshness - Noise, Vibration and Harshness (NVH)
Description and Operation
Noise, vibration and harshness (NVH) is becoming more important as vehicles become more sophisticated and passenger
comfort levels increase. This section is designed to aid in the diagnosis, testing and repair of NVH concerns.
Noise is defined as sounds not associated with the operation of passenger compartment equipment that interface with
customer satisfaction.
Vibration is defined as impulses felt by the customer that are not caused by road surface changes.
Harshness is a ride quality issue where the customer feels that the vehicle response to the road surface is sharply
transmitted to the customer.
Diagnostic Theory
Diagnosis is more than just following a series of interrelated steps in order to find the solution to the specific condition. It is a
way of looking at systems that are not functioning the way they should and finding out why. Also it is knowing how the system
should work and whether it is working correctly.
There are basic rules for diagnosis. If these rules are followed, the cause of the condition is usually found the first time
through the system.
Know the System
Know how the parts go together.
Know how the system operates as well as its limits and what happens when the system goes wrong.
Sometimes this means checking the system against one that is known to be working correctly.
Know the History of the System
A clue in any one of these areas may save time:
How old or new is the system?
What kind of treatment has it had?
Has it been repaired in the past in such a manner that might relate to the present condition?
What is the repair history?
Know the History of the Condition
Did it start suddenly or appear gradually?
Was it related to some other occurrence such as a collision or previous part renewal?
Know how the condition made itself known; it may be an important clue to the cause.
Know the Probability of Certain Conditions Developing
Look for the simple rather than the complex.
For example:
- Electrical conditions usually occur at connections rather than components.
- An engine no-start is more likely to be caused by a loose wire or small adjustment rather than a sheared-off
camshaft.
Know the difference between impossible and improbable. Certain failures in a system can be improbable but still
happen.
New parts are just that, new. It does not mean they are always good functioning parts.
Do Not Cure the Symptom and Leave the Cause
Lowering the pressure in a front tire may correct the condition of a vehicle leaning to one side, but it does not correct the
original condition.
Be Positive the Cause is Found
Double check the findings.
What caused a worn component?
A loose transmission or engine mount could indicate that other mounts are also loose.
Diagnostic Charts
Charts are a simple way of expressing the relationship between basic logic and a physical system of components. They help
discover the cause of a condition in the least time. Diagnostic charts combine many areas of diagnosis into one visual display:
probability of certain things occurring in a system
speed of checking certain components or functions before others
simplicity of carrying out certain tests before others
elimination of checking huge portions of a system by carrying out simple tests
certainty of narrowing down the search to a small portion before carrying out in-depth testing
The fastest way to find a condition is to work with the tools that are available. This means working with proven diagnostic
charts and the correct special equipment for the system.
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Published: 16-Sep-2013
Noise, Vibration and Harshness - Noise, Vibration and Harshness (NVH)
Diagnosis and Testing
Principle of Operation
For a detailed description of Noise, Vibration and Harshness issues, refer to the Description and Operation section of the
workshop manual.
REFER to: Noise, Vibration and Harshness (NVH) (100-04 Noise, Vibration and Harshness, Description and Operation).
Inspection and Verification
1. Verify the customer's concerns by operating the vehicle to duplicate the condition.
2. Visually inspect the vehicle to determine any obvious cause(s) of the concern(s).
3. If the inspection reveals obvious causes that can be readily identified, repair as necessary.
4. If the concern(s) remains after the inspection, determine the symptom(s) and refer to the Symptom Chart.
How To Use This Diagnostic Procedure Section
Noise, vibration and harshness (NVH) concerns have become more important as vehicles have become more sensitive to
these vibrations. This section is designed as an aid to identifying these situations
The section provides diagnostic procedures based on symptoms. If the condition occurs at high speed, for instance, the
most likely place to start is under High Speed Shake
The road test procedure will tell how to sort the conditions into categories and how to tell a vibration from a shake
A series of Road Test Quick Checks is provided to make sure that a cause is either pinpointed or eliminated
Name the condition, proceed to the appropriate section and locate the correct diagnosis. When the condition is
identified, the job is partly done
Follow the diagnostic procedure as outlined
Quick Checks are described within the step, while more involved tests and adjustments are outlined in General
Procedures
Always follow each step exactly and make notes to recall important findings later
Customer Interview
The road test and customer interview (if available) provide information that will help identify the concerns and will provide
direction to the correct starting point for diagnosis.
Identify the Condition
NVH problems usually occur in a number of areas:
tires
engine accessories
suspension
driveline
air leakage (wind noise)
squeaks and rattles
heating ventilation and air conditioning (HVAC)
electrical (e.g. motor noise)
transmission
engine
It is important, therefore, that an NVH concern be isolated into its specific area(s) as soon as possible. The easiest and
quickest way to do this is to carry out the Road Test as outlined.
Noise Diagnostic Procedure
Non-Axle Noise
The five most important sources of non-axle noise are exhaust, tires, roof racks, trim and mouldings, and transmission.
Therefore, make sure that none of the following conditions are the cause of the noise before proceeding with a driveline tear
down and diagnosis.
Under certain conditions, the pitch of the exhaust may sound very much like gear noise. At other times, it can be
mistaken for a wheel bearing rumble
Tires, especially snow tires, can have a high pitched tread whine or roar, similar to gear noise. Radial tires, to some
degree, have this characteristic. Also, any non-standard tire with an unusual tread construction may emit a roar or
whine type noise
Trim and mouldings can also cause whistling or a whining noise
Clunk may be a metallic noise heard when the automatic transmission is engaged in reverse or drive, or it may occur
when the throttle is applied or released. It is caused by backlash somewhere in the driveline
Bearing rumble sounds like marbles being tumbled. This condition is usually caused by a damaged wheel bearing
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Noise Conditions
Gear noise is typically a howling or whining due to gear damage or incorrect bearing preload. It can occur at various
speeds and driving conditions, or it can be continuous
Chuckle is a particular rattling noise that sounds like a stick against the spokes of a spinning bicycle wheel. It occurs
while decelerating from approximately 64 km/h (40 miles/h) and can usually be heard all the way to a stop. The
frequency varies with vehicle speed
Knock is very similar to chuckle, though it may be louder and occurs on acceleration or deceleration. The tear down will
disclose what has to be corrected
Check and rule out tires, exhaust and trim items before disassembling the transmission to diagnose and correct gear noise.
The noises described under Road Test usually have specific causes that can be diagnosed by observation as the unit is
disassembled. The initial clues are the type of noise heard on the road test and the driving conditions.
Vibration Conditions
wear. NOTE: New Constant Velocity (CV) joints should not be installed unless disassembly and inspection revealed unusual
Clicking, popping or grinding noises may be caused by the following:
Cut or damaged CV joint boots resulting in inadequate or contaminated lubricant in the outboard or inboard CV joint
bearing housings
Loose CV joint boot clamps
Another component contacting the rear drive half shaft
Worn, damaged or incorrectly installed wheel bearing, suspension or brake component
Vibration at highway speeds may be caused by the following:
Out-of-balance front or rear wheels
Out-of-round tires
Driveline imbalance
Driveline run-out (alignment)
NOTE: Rear drive half shafts are not balanced and are not likely to contribute to rotational vibration disturbance.
Shudder or vibration during acceleration (including from rest) may be caused by the following:
Driveline alignment
Excessively worn or damaged outboard or inboard CV joint bearing housing
Excessively high CV joint operating angles caused by incorrect ride height. Check ride height, verify correct spring rate
and check items under Inoperative Conditions
Excessively worn driveshaft components
Leakage Conditions
1. Inspect the CV joint boots for evidence of cracks, tears or splits.
2. Inspect the underbody for any indication of grease splatter in the vicinity of the rear drive half shaft, outboard and
inboard CV joint boot locations, which is an indication of CV joint boot or CV joint boot clamp damage.
3. Inspect the inboard CV joint bearing housing seal for leakage.
Inoperative Conditions
If a CV joint or rear drive half shaft pull-out occurs, check the following:
suspension components for correct location, damage or wear
bushings for wear
subframe for damage
bent or worn components
- Stabilizer bar link
- Left-hand rear suspension lower arm and bushing
- Right-hand rear suspension lower arm and bushing
- Rear wheel hub and rear drive half shaft
Road Test
A gear-driven unit will produce a certain amount of noise. Some noise is acceptable and may be audible at certain speeds or
under various driving conditions as on a newly paved blacktop road. The slight noise is in no way detrimental and must be
considered normal.
The road test and customer interview (if available) provide information needed to identify the condition and give direction to
the correct starting point for diagnosis.
1. Make notes throughout the diagnosis routine. Make sure to write down even the smallest piece of information, because
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it may turn out to be the most important.
2. Do not touch anything until a road test and a thorough visual inspection of the vehicle have been carried out. Leave the
tire pressures and vehicle load just where they were when the condition was first observed. Adjusting tire pressures,
vehicle load or making other adjustments may reduce the conditions intensity to a point where it cannot be identified
clearly. It may also inject something new into the system, preventing correct diagnosis.
3. Make a visual inspection as part of the preliminary diagnosis routine, writing down anything that does not look right.
Note tire pressures, but do not adjust them yet. Note leaking fluids, loose nuts and bolts, or bright spots where
components may be rubbing against each other. Check the luggage compartment for unusual loads.
4. Road test the vehicle and define the condition by reproducing it several times during the road test.
5. Carry out the Road Test Quick Checks as soon as the condition is reproduced. This will identify the correct diagnostic
procedure. Carry out the Road Test Quick Checks more than once to verify they are providing a valid result. Remember,
the Road Test Quick Checks may not tell where the concern is, but they will tell where it is not.
Road Test Quick Checks
1. 24-80 km/h (15-50 miles/h): With light acceleration, a moaning noise is heard and possibly a vibration is felt in the
front floor pan. It is usually worse at a particular engine speed and at a particular throttle setting during acceleration at
that speed. It may also produce a moaning sound, depending on what component is causing it. Refer to Tip-In Moan in
the Symptom Chart.
2. Acceleration/deceleration: With slow acceleration and deceleration, a shake is sometimes noticed in the steering
wheel/column, seats, front floor pan, front door trim panel or front end sheet metal. It is a low frequency vibration
(around 9-15 cycles per second). It may or may not be increased by applying brakes lightly. Refer to Idle Boom/Shake
/Vibration in the Symptom Chart.
3. High speed: A vibration is felt in the front floor pan or seats with no visible shake, but with an accompanying sound or
rumble, buzz, hum, drone or booming noise. Coast with the clutch pedal depressed or shift control selector lever in
neutral and engine idling. If vibration is still evident, it may be related to wheels, tires, front brake discs, wheel hubs
or front wheel bearings. Refer to High Speed Shake in the Symptom Chart.
4. Engine rpm sensitive: A vibration is felt whenever the engine reaches a particular rpm. It will disappear in neutral
coasts. The vibration can be duplicated by operating the engine at the problem rpm while the vehicle is stationary. It
can be caused by any component, from the accessory drive belt to the torque converter which turns at engine speed
when the vehicle is stopped. Refer to High Speed Shake in the Symptom Chart.
5. Noise/vibration while turning: Clicking, popping, or grinding noises may be due to a worn, damaged, or incorrectly
installed front wheel bearing, rear drive half shaft or CV joint.
6. Noise/vibration that is road speed relative: This noise/vibration can be diagnosed independent of engine speed or gear
selected (engine speed varies but torque and road speed remain constant). The cause may be a rear drive
axle/differential whine.
Road Conditions
An experienced technician will always establish a route that will be used for all NVH diagnosis road tests. The road selected
should be reasonably smooth, level and free of undulations (unless a particular condition needs to be identified). A smooth
asphalt road that allows driving over a range of speeds is best. Gravel or bumpy roads are unsuitable because of the additional
road noise produced. Once the route is established and consistently used, the road noise variable is eliminated from the test
results.
NOTE: Some concerns may be apparent only on smooth asphalt roads.
If a customer complains of a noise or vibration on a particular road and only on a particular road, the source of the concern
may be the road surface. If possible, try to test the vehicle on the same type of road.
Vehicle Preparation
Carry out a thorough visual inspection of the vehicle before carrying out the road test. Note anything which is unusual. Do not
repair or adjust any condition until the road test is carried out, unless the vehicle is inoperative or the condition could pose a
hazard to the technician.
After verifying the condition has been corrected, make sure all components removed have been installed.
Lift Test
After a road test, it is sometimes useful to do a similar test on a lift.
When carrying out the high-speed shake diagnosis or engine accessory vibration diagnosis on a lift, observe the following
precautions:
WARNING: If only one drive wheel is allowed to rotate, speed must be limited to 55 km/h (35 miles/h) indicated on the
speedometer since actual wheel speed will be twice that indicated on the speedometer. Speed exceeding 55 km/h (35 miles/h)
or allowing the drive wheel to hang unsupported could result in tire disintegration, differential failure, constant velocity joint
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and drive half shaft failure, which could cause serious personal injury and extensive vehicle damage. Failure to follow these
instructions may result in personal injury.
CAUTION: The suspension should not be allowed to hang free. When the CV joint is run at a very high angle, extra
vibration as well as damage to the seals and joints can occur.
The rear suspension lower arm should be supported as far outboard as possible. To bring the vehicle to its correct ride height,
the full weight of the vehicle should be supported in the rear by floor jacks. REFER to: (100-02 Jacking and Lifting)
Jacking (Description and Operation), Lifting (Description and Operation).
1. Raise and support the vehicle. REFER to: (100-02 Jacking and Lifting)
Jacking (Description and Operation), Lifting (Description and Operation).
2. Explore the speed range of interest using the Road Test Quick Checks as previously described.
3. Carry out a coast down in neutral. If the vehicle is free of vibration when operating at a steady indicated speed and
behaves very differently in drive and coast, a transmission concern is likely.
Note, however, that a test on the lift may produce different vibrations and noises than a road test because of the effect of the
lift. It is not unusual to find vibrations on the lift that were not found in the road test. If the condition found on the road can
be duplicated on the lift, carrying out experiments on the lift may save a great deal of time.
Exhaust Neutralization Procedure
1. Raise vehicle on lift and slacken all exhaust fixings.
2. With all fixings loose, neutralize the exhaust system.
3. Tighten all fixings to correct torque, starting at the rear-most point working towards the front of the vehicle.
Symptom Chart
Symptom Possible Cause Action High-speed shake
Wheel end vibration
Engine/transmission
Driveline GO to Pinpoint Test A. Tip-in moan
Air cleaner
Power steering
Powertrain
Engine mounts
Exhaust system GO to Pinpoint Test B. Idle boom/shake/vibration, or shudder
Cable(s)/hoses(s)
Intake air distribution and filtering system
Engine mounts
Exhaust system
Belt/pulleys GO to Pinpoint Test C. Wheel end vibration analysis
Suspension/rear drive halfshaft and CV joints
Tires/wheels
Wheel bearings
CV joint boots GO to Pinpoint Test D. Non-axle noise
Trim/mouldings
A/C system
Accessories GO to Pinpoint Test E. Pinpoint Tests
NOTE: These Pinpoint Tests are designed to take the technician through a step-by-step diagnosis procedure to determine
the cause of a condition. It may not always be necessary to follow the chart to its conclusion. Carry out only the Pinpoint Test
steps necessary to correct the condition. Then check operation of the system to make sure the condition is corrected.
After verifying that the condition has been corrected, make sure all components removed have been installed.
PINPOINT TEST A : HIGH-SPEED SHAKE TEST DETAILS/RESULTS/ACTIONS www.JagDocs.com
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PINPOINT TEST B : TIP-IN MOAN TEST
CONDITIONS DETAILS/RESULTS/ACTIONS B1: CHECK THE AIR CLEANER 1 Check the air cleaner.
Check the air cleaner, inlet tube, outlet tube, resonators and all other components associated with
the air induction system for correct installation and tightness of all connections. Are the components OK? Yes
GO to B2. No
Correct the condition. Repeat the Road Test as outlined. B2: CHECK THE EXHAUST SYSTEM 1 Carry out the exhaust system neutralizing procedure in this section. Is the exhaust system OK? Yes
GO to B3. No
Repair as necessary. Restore vehicle. Repeat the Road Test as outlined. B3: CHECK THE POWER STEERING 1 Remove the auxiliary drive belt and test for tip-in moan. Is the tip-in moan OK? Yes
Repair the power steering as necessary. For additional information, refer to Section 211-00.
No
Check and install new engine/transmission mounts as necessary. Repeat Road Test as outlined.
PINPOINT TEST C : IDLE BOOM/SHAKE/VIBRATION/SHUDDER TEST
CONDITIONS DETAILS/RESULTS/ACTIONS C1: CHECK CABLE/HOSES 1 Check the engine compartment for any component that may be grounding between the engine and body or chassis. Example: air conditioning (A/C) hoses. Are the components OK? Yes
GO to C2. No
Correct the condition. Repeat the Road Test as outlined. C2: CHECK THE COOLING RADIATOR 1 Check the engine cooling radiator mountings and bushings for security and condition. Check the radiator installation for any component that may have a touch condition. Are the installation and bushings OK? Yes
GO to C3. No
Correct the condition. Repeat the Road Test as outlined. C3: CHECK THE EXHAUST SYSTEM 1 Carry out the exhaust system neutralizing procedure in this section. Is the exhaust system OK? Yes
Check and install new engine/transmission mounts as necessary. Repeat Road Test as outlined.
No
Repair as necessary. Repeat Road Test.
PINPOINT TEST D : WHEEL END VIBRATION ANALYSIS TEST CONDITIONS DETAILS/RESULTS/ACTIONS D1: INSPECT THE TIRES 1 Inspect the tires.
Raise and support the vehicle. REFER to: (100-02 Jacking and Lifting)
Jacking (Description and Operation), Lifting (Description and Operation).
Inspect the tires for:
Correct tire size
Tire/wheel compatibility
Wear or damage
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Tire beads correctly seated Are the tires OK? Yes
GO to D2. No
Inspect the wheels. For additional information, refer to Section 204-00. D2: INSPECT WHEEL BEARINGS 1 Inspect the wheel bearings. For additional information, refer to Section 204-00. Are the wheel bearings OK? Yes
GO to D3. No
Repair as necessary. Repeat the Road Test as outlined. D3: INSPECT THE CONSTANT VELOCITY (CV) JOINT BOOTS 1 Inspect the CV joint boots. Spin the rear tire by hand
Inspect for evidence of cracks, tears, splits or splattered grease Are the CV joint boots OK? Yes
GO to D4. No
Repair as necessary. Repeat the Road Test as outlined. D4: INSPECT WHEEL AND TIRE RUNOUT 1 Inspect the wheel and tire runout. Carry out the Wheel and Tire Check procedure.
REFER to: Lifting (100-02 Jacking and Lifting, Description and Operation). Is the wheel and tire runout OK? Yes
Balance the wheels and tires. Refer to the wheel balance equipment manufacturers instructions.
No
Repair as necessary.
REFER to: Lifting (100-02 Jacking and Lifting, Description and Operation). Repeat the Road Test as outlined.
PINPOINT TEST E : NON-AXLE NOISE TEST
CONDITIONS DETAILS/RESULTS/ACTIONS E1: INSPECT VEHICLE TRIM 1 Check the grille and trim mouldings to see if they are the source of the noise. Are the vehicle trim components causing the noise? Yes
Install new trim or repair as necessary. For additional information, refer to Section 501-08.
No
GO to E2. E2: CHECK THE A/C SYSTEM FOR NOISE 1 Check the A/C system components for noise by turning the A/C system on and off. Is the A/C system causing the noise? Yes
Diagnose the A/C system.
REFER to: Lifting (100-02 Jacking and Lifting, Description and Operation). No
GO to E3. E3: CHECK NON-FACTORY ACCESSORIES 1 Inspect any accessories for being the source of the noise. Example: grounding body-to-frame, antennas, visors, bug deflectors and fog lights? Are the accessories the cause of the noise? Yes
Adjust, repair or install new accessories or fasteners as required.
No
Verify the customer concern.