I have a 93 xlt auto. Just bought it last week. This is difficult to explain but ill give it a shot. As I am driving along, the gear in which the truck is in doesn't seem to matter, it will suddenly start vibrating and humming loud. It seems to happen when it is nearing a shift in gear and stops if I hit the gas good enough to romp on it. It will do it again if I merely press the gas.
vibration
- Thread starter numsleven
- Start date
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yo numsleven,
WELCOME!
At idle; do you feel any vibes?
w/tranny in Park & parking brake on and foot hard down on brake pedal: any vibes?
with same as above, press accel pedal, any vibes?
If you can feel vibes in any abvoe; a helper may be be able to use a long screwdriver, pipe section etc. to press against (BE WARY of FAN, BELTS, Hot Engine, etc.)
various parts described below; such as in the Typical Low-Speed Vibrations (Less Than 72 km/h [45 mph])
Following is by Ford; (if you go to a dealer, this is what will occur and charged for....)
Noise Conditions
If noise is produced as part of a vibration condition, correcting the vibration will eliminate the noise. If the noise is related to a specific component or system, refer to the appropriate service manual section for further diagnosis.
Vibration Conditions
Vibration, technically, is a high-frequency trembling, shaking or grounding condition, felt or heard, that is constant or variable in level and occurs during a portion of the total operating speed range. The types of vibrations that can be felt in the vehicle can be divided into three groups:
vibrations of various unbalanced rotating parts of the vehicle
body and frame vibrations excited by powertrain, wind or road inputs
tip-in moans or resonance vibrations from stressed engine or exhaust system mounts or driveline flexing modes
For engine or accessory vibration, all speeds, refer to Pinpoint Test D in the Diagnosis and Testing portion of this section.
Noise, Vibration and Harshness Pinpoint Tests This is for a 96, but =
For high-speed shake/vibration, 80 km/h (50 mph) and up:
Refer to Pinpoint Test A in the Diagnosis and Testing portion of this section and to Section 04-04 for tire conditions contributing to shake/vibration. SEE
Refer to hub and rotor runout checks in Section 06-00.
For tip-in moan, refer to Symptom Charts in the Diagnosis and Testing portion of this section. If the symptom still exists, refer to Pinpoint Test B in the Diagnosis and Testing portion of this section or the engine assembly in Section 03-01A, Section 03-01B, Section 03-01C or Section 03-01D.
For brake shudder, refer to Section 06-00.
Vehicle vibrations can also be subdivided into those that occur at low speeds and those that are most noticeable at higher speeds. Since the dividing line between low and higher speed vibrations is not clear, there will be vibrations that overlap the two ranges.
Typical Low-Speed Vibrations (Less Than 72 km/h [45 mph])
exhaust vibration
engine harshness
driveline vibration due to improper driveline angles
power steering pump disturbances
air conditioner compressor or drive belt (8620) vibrations
take-off shudder (driveline problems)
brake roughness or harshness
driveline roughness
driveline slip-yoke or rear axle universal joint ****** (4851), automatic or manual transmission clutch slippage
Typical High-Speed Vibrations (Above 72 km/h [45 mph])
rear axle universal joint ****** runout or imbalance
driveshaft (4602) imbalance
excessive tire-wheel and drum assembly imbalance
tire roughness due to high non-uniformity (force variation) or out-of-balance condition
rear axle pinion gear pitch line runout
excessive tire and wheel runout
worn suspension components
front end accessory vibrations
exhaust vibration (greatly reduced in exhaust systems de-coupled by a flexible coupling and mounted with blade and block hangers)
Harshness Conditions
Harshness is the term commonly used to describe the ride quality concern of the vehicle. A hard ride or harshness is usually caused by the tires or suspension system, namely:
overinflated, wrong size or wrong type tire installed on the vehicle
suspension not sufficiently lubricated
worn suspension components
suspension components installed with preload on pivot point, bearings and bushings
vehicles equipped with tires not specified by the manufacturer (different brand tires often give different ride qualities to the vehicle)
bent or bound-up shock absorbers
heavy-duty components installed on vehicle
Other harshness conditions that affect ride quality may be summarized as follows:
Road Test
NVH diagnosis should always start with the road test.
Noise, vibration and harshness (NVH) usually occurs in four areas: tires, engine accessories, suspension and powertrain. It is important, therefore, that an NVH concern be isolated into its specific area as soon as possible. The easiest and quickest way to do this is to perform a road test.
NVH Diagnostic Locator
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. The slight noise is in no way detrimental and must be considered normal.
Make notes throughout diagnostic routine. It will help cover all bases when starting to add up clues. Use a road test form that includes space for comments. Write down even the smallest bit of information, as it may turn out to be most important.
Road test the vehicle, and define the condition by reproducing it several times during the road test.
Perform the road test quick checks as soon as the condition is reproduced. This will identify the appropriate diagnostic procedure. Run through the quick checks more than once to make sure they are getting a usable result. Remember, the road test quick checks may not tell where the concern is, but they will tell where it is not.
Make a visual inspection as part of the preliminary diagnostic routine, writing down anything that does not look right. Note tire pressures, leaking fluids, loose nuts and/or bolts, or bright spots where components may be rubbing against each other. Check cargo area for unusual loads.
Some hints on performing a road test for the diagnosis of NVH complaints follow.
Neutral Engine Run-Up Test (NERU)
A very useful first step in the road test is a neutral engine run-up (NERU) test. It identifies engine related vibrations and helps in sorting out vibrations that are found in the road test.
This test takes only a minute or two and represents time well spent in testing.
If the vehicle is equipped with a tachometer, it can be used. Otherwise, a tach should be connected. A tach is absolutely necessary in both the NERU test and the road test.
Locate the vehicle away from other vehicles and walls which may reflect sound differently than a road reflects sound.
Put the vehicle in N (neutral) or P (park) and do not set the parking brake or press on the service brake since these are not engaged in a road test. Pressing on the service brake puts forces into the brake and clutch pedal support and into the dash panel that are not present in driving. A similar situation arises with the parking brake.
Run the engine up from idle to approximately 4000 rpm and note any moans, vibrations, noises, etc., and the rpm at which they occur. Sometimes it is possible to "tune in" on these by running up and down in rpm to determine a precise rpm at which they occur; in other cases they will fall over a broad range of rpm. This establishes a baseline against which driving vibrations can be measured.
If you suspect that the exhaust system is vibrating, hang a ring of keys or something similar from the tailpipe and listen for the rattling of the keys as the engine is run up and down. Sometimes it is very clear with just this simple test that the exhaust system is responsible.
Some exhaust systems contain flexible couplings and may not require evaluation unless the exhaust system is damaged.
If you suspect the air conditioning system or drive belt, turn on the air conditioning system before performing the NERU test. If a noise occurs at a specific rpm, turn the air conditioning system off and on to see if the noise is connected to the air conditioning compressor or A/C system lines.
Results of the NERU test should be compared with the results of the road test to sort out vibrations and noises caused by the engine from those caused by the transmission, driveshaft or axle. If, during the road test, a vibration or noise occurs at a particular speed, try operating in another gear at the same speed. This changes the engine rpm and helps to sort out engine induced vibrations and noises. If it occurs at a particular rpm, use different gears to test at the same rpm at different road speeds. Turn the air conditioning system off and on at road speeds where noise occurs to isolate air conditioning system problems.
Drive Engine Run-Up Test (DERU)
CAUTION: Do not conduct this test for over 30 seconds, or without periodic driving or shifting to neutral to circulate transmission lubricant, otherwise, the transmission will overheat causing severe damage to the automatic transmission.
Set both the parking brake and service brake and take care to perform the test with enough space ahead of the vehicle to eliminate the possibility of an accident should the vehicle unintentionally lurch forward.
Put the transmission in D (drive) and run the engine up and down between idle and approximately 2000 rpm. Note the nature of any vibrations and noises and when these concerns occur in relation to engine rpm. This test is particularly good for examination of the exhaust system, and hanging keys on the tailpipe can serve as a "telltale" indicator.
The following worksheet is invaluable for recording customer comments as well as inspection and road test data.
Road Test Form
Road Test Quick Checks
24-80 km/h (15-50 mph): With light acceleration, a moaning noise is heard, and possibly a vibration is felt in the floorpan. 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 Pinpoint Test B.
Slow acceleration and deceleration: A shake is sometimes noticed in the steering wheel (3600)/steering column tube, seats, floorpan, trim panels 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 Pinpoint Test A.
At road speed: A vibration is felt in the floorpan or seats with no visible shake, but with an accompanying sound or rumble, buzz, hum, drone or booming noise. Coast with transmission control selector lever in NEUTRAL and engine idling. If vibration is still evident, it may be related to wheels, tires, front disc brake rotors (1125), rear brake drums (1126) wheel hubs (1104), wheel bearings (4000), driveshaft balance, rear axle universal joint ****** runout or transmission balance.
Refer to Pinpoint Test A.
0-High Speed: A vibration is felt whenever the engine reaches a particular rpm. It will disappear in NEUTRAL coast. The vibration can be duplicated by operating the engine at the problem rpm while the vehicle is parked. 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 Pinpoint Test D.
Road Conditions
The type of road and its surface condition are important factors in the road test. A smooth asphalt road that allows driving over a range of speeds is best. The brushed concrete road surface found on many expressways and the coarse aggregate sometimes found in concrete can mask many vehicle noises and make NVH diagnosis difficult.
If the 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 condition of the road surface and not the vehicle. If possible, try to test on the same type of surface. In this case, a smooth asphalt road may not be the best.
Vehicle Preparation
Check and verify if vehicle is equipped with original equipment (OE), type, size and brand wheels and tires. If non-original equipment (OE) wheels and or tires are installed, it may be necessary to substitute original equipment (OE) level tire/wheel assemblies to eliminate this factor before proceeding with the NVH diagnosis. Check and verify that ride height of vehicle has not been modified.
Check and set tire pressure.
Unlock the front hubs and back up approximately 20 feet to make sure of hub disengagement if the vehicle is a 4x4.
Remove any externally mounted accessories such as luggage racks, or magnetic base or the antenna which may cause wind noise that interferes with NVH diagnosis.
Use a tachometer.
Note the fuel level. Some vehicles change in their response to various excitations when the fuel level changes. If the customer mentions that the concern does not occur all the time, this might be a factor.
Try to duplicate the conditions with the customer present, particularly the speed and throttle operation. It is not uncommon to find concerns which the customer didn't notice so it is important to identify the specific concern causing the complaint.
Find the speed where the concern is most severe.
Turn the air conditioning system off and on to isolate air conditioning system impact on the noise. Accelerate gently through this speed to a few mph above it and then coast back down a few mph below it and note if the concern changes character when driving through or coasting down.
Repeat this procedure if necessary to get a feeling for the behavior. Then drive about five mph above the speed, put the transmission in neutral and coast down. Note any change in behavior.
Try "floating" the driveline by backing off slightly on the throttle at the problem speed. The idea is to unload the axle gears and the universal joints as much as possible. This test is difficult to master and sometimes it helps to test on a slight downgrade so that gravity is counteracting the aerodynamic drag.
If the concern does not change in all these modes of operation, the cause may well be driveline imbalance since the imbalance is not changed by the throttle position.
If there is a distinct change in the character or intensity between the drive and coast modes of operation, the concern is not likely imbalance but is most likely due to the axle or the universal joints since they are sensitive to the load on the driveline. (The axle pinion gear teeth are machined on two separate machines. One machine does the drive side of the teeth, another does the coast side. Hence there can be a great difference in performance between driving and coasting in gear.) If the noise and/or vibration goes away when the driveline is "floated" or when coasting through the speed range in neutral, the diagnosis is strengthened. Driveline imbalance does not go away in a neutral coast, but axle and joint concerns may.
To become familiar with the symptoms of imbalance and to determine if driveline imbalance exists on the vehicle, intentionally imbalance the driveline. This can be done by installing three hose clamps with ***** heads aligned on the rear of the driveshaft. Test drive the vehicle again. If the same vibration is still present but now intensified, the concern is driveline imbalance. If a new vibration is now present as a result of the intentional imbalance, the original condition would not be caused by driveline imbalance.
Hoist Test
After a road test, but only after a road test, it is sometimes useful to do a similar test on a hoist. Use an axle hoist, not a frame hoist. An axle hoist will not change the driveline angles. If only a frame hoist is available, axle stands should be used.
Elevate the rear wheels slightly. Check to make sure that both are turning, and run the engine up with the vehicle in gear.
Explore the speed range of interest using the drive/cruise/coast/float tests as described under Vehicle Preparation.
A coast down in neutral should also be conducted. If the vehicle is free of vibration when operating at a steady indicated speed and behaves very differently in drive and coast, an axle concern is likely.
A test on the hoist may produce different vibrations and noises than a road test because of the effect of the hoist on the rear axle. It is not unusual to find vibrations on the hoist that were not found in the road test and in most instances they may be ignored. Similarly, some problems may be apparent only on smooth asphalt roads. If the condition that was found on the road can be duplicated on the hoist, a great deal of time can be saved by doing experiments on the hoist.
========
E4OD Torque Converter:
If the shudder (or vibe) occurs;
a) during the 3-4 or 4-3 shift at HEAVY throttle,
or b at 40mph in 2, OD OFF, and OD, or c) at the same RPM in every gear, or d) coasting, cruising, or in R, or e) during extended light braking, then it is NOT TC clutch shudder;
The following is a list of common vehicle concerns that have been misdiagnosed as torque converter clutch shudder. For diagnosis of the following items, refer to the appropriate sections of the workshop manual and the Powertrain Control/Emissions Diagnosis manual (PCED).
Spark plugs - check for cracks, high resistance or broken insulators. P
lug wires.
Fuel injector - filter may be plugged.
Fuel contamination - engine runs poorly.
EGR valve - valve may let in too much exhaust gas and cause engine to run lean.
Vacuum leak - engine will not get correct air/fuel mixture.
MAP sensor - improper air/fuel mixture.
HO2S sensor - too rich/lean air/fuel mixture.
Fuel pressure - may be too low.
Engine mounts -loose/damaged mounts can cause vibration concerns.
Axle joints - check for vibration
WELCOME!
At idle; do you feel any vibes?
w/tranny in Park & parking brake on and foot hard down on brake pedal: any vibes?
with same as above, press accel pedal, any vibes?
If you can feel vibes in any abvoe; a helper may be be able to use a long screwdriver, pipe section etc. to press against (BE WARY of FAN, BELTS, Hot Engine, etc.)
various parts described below; such as in the Typical Low-Speed Vibrations (Less Than 72 km/h [45 mph])
Following is by Ford; (if you go to a dealer, this is what will occur and charged for....)
Noise Conditions
If noise is produced as part of a vibration condition, correcting the vibration will eliminate the noise. If the noise is related to a specific component or system, refer to the appropriate service manual section for further diagnosis.
Vibration Conditions
Vibration, technically, is a high-frequency trembling, shaking or grounding condition, felt or heard, that is constant or variable in level and occurs during a portion of the total operating speed range. The types of vibrations that can be felt in the vehicle can be divided into three groups:
vibrations of various unbalanced rotating parts of the vehicle
body and frame vibrations excited by powertrain, wind or road inputs
tip-in moans or resonance vibrations from stressed engine or exhaust system mounts or driveline flexing modes
For engine or accessory vibration, all speeds, refer to Pinpoint Test D in the Diagnosis and Testing portion of this section.
Noise, Vibration and Harshness Pinpoint Tests This is for a 96, but =
For high-speed shake/vibration, 80 km/h (50 mph) and up:
Refer to Pinpoint Test A in the Diagnosis and Testing portion of this section and to Section 04-04 for tire conditions contributing to shake/vibration. SEE
Refer to hub and rotor runout checks in Section 06-00.
For tip-in moan, refer to Symptom Charts in the Diagnosis and Testing portion of this section. If the symptom still exists, refer to Pinpoint Test B in the Diagnosis and Testing portion of this section or the engine assembly in Section 03-01A, Section 03-01B, Section 03-01C or Section 03-01D.
For brake shudder, refer to Section 06-00.
Vehicle vibrations can also be subdivided into those that occur at low speeds and those that are most noticeable at higher speeds. Since the dividing line between low and higher speed vibrations is not clear, there will be vibrations that overlap the two ranges.
Typical Low-Speed Vibrations (Less Than 72 km/h [45 mph])
exhaust vibration
engine harshness
driveline vibration due to improper driveline angles
power steering pump disturbances
air conditioner compressor or drive belt (8620) vibrations
take-off shudder (driveline problems)
brake roughness or harshness
driveline roughness
driveline slip-yoke or rear axle universal joint ****** (4851), automatic or manual transmission clutch slippage
Typical High-Speed Vibrations (Above 72 km/h [45 mph])
rear axle universal joint ****** runout or imbalance
driveshaft (4602) imbalance
excessive tire-wheel and drum assembly imbalance
tire roughness due to high non-uniformity (force variation) or out-of-balance condition
rear axle pinion gear pitch line runout
excessive tire and wheel runout
worn suspension components
front end accessory vibrations
exhaust vibration (greatly reduced in exhaust systems de-coupled by a flexible coupling and mounted with blade and block hangers)
Harshness Conditions
Harshness is the term commonly used to describe the ride quality concern of the vehicle. A hard ride or harshness is usually caused by the tires or suspension system, namely:
overinflated, wrong size or wrong type tire installed on the vehicle
suspension not sufficiently lubricated
worn suspension components
suspension components installed with preload on pivot point, bearings and bushings
vehicles equipped with tires not specified by the manufacturer (different brand tires often give different ride qualities to the vehicle)
bent or bound-up shock absorbers
heavy-duty components installed on vehicle
Other harshness conditions that affect ride quality may be summarized as follows:
Road Test
NVH diagnosis should always start with the road test.
Noise, vibration and harshness (NVH) usually occurs in four areas: tires, engine accessories, suspension and powertrain. It is important, therefore, that an NVH concern be isolated into its specific area as soon as possible. The easiest and quickest way to do this is to perform a road test.
NVH Diagnostic Locator
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. The slight noise is in no way detrimental and must be considered normal.
Make notes throughout diagnostic routine. It will help cover all bases when starting to add up clues. Use a road test form that includes space for comments. Write down even the smallest bit of information, as it may turn out to be most important.
Road test the vehicle, and define the condition by reproducing it several times during the road test.
Perform the road test quick checks as soon as the condition is reproduced. This will identify the appropriate diagnostic procedure. Run through the quick checks more than once to make sure they are getting a usable result. Remember, the road test quick checks may not tell where the concern is, but they will tell where it is not.
Make a visual inspection as part of the preliminary diagnostic routine, writing down anything that does not look right. Note tire pressures, leaking fluids, loose nuts and/or bolts, or bright spots where components may be rubbing against each other. Check cargo area for unusual loads.
Some hints on performing a road test for the diagnosis of NVH complaints follow.
Neutral Engine Run-Up Test (NERU)
A very useful first step in the road test is a neutral engine run-up (NERU) test. It identifies engine related vibrations and helps in sorting out vibrations that are found in the road test.
This test takes only a minute or two and represents time well spent in testing.
If the vehicle is equipped with a tachometer, it can be used. Otherwise, a tach should be connected. A tach is absolutely necessary in both the NERU test and the road test.
Locate the vehicle away from other vehicles and walls which may reflect sound differently than a road reflects sound.
Put the vehicle in N (neutral) or P (park) and do not set the parking brake or press on the service brake since these are not engaged in a road test. Pressing on the service brake puts forces into the brake and clutch pedal support and into the dash panel that are not present in driving. A similar situation arises with the parking brake.
Run the engine up from idle to approximately 4000 rpm and note any moans, vibrations, noises, etc., and the rpm at which they occur. Sometimes it is possible to "tune in" on these by running up and down in rpm to determine a precise rpm at which they occur; in other cases they will fall over a broad range of rpm. This establishes a baseline against which driving vibrations can be measured.
If you suspect that the exhaust system is vibrating, hang a ring of keys or something similar from the tailpipe and listen for the rattling of the keys as the engine is run up and down. Sometimes it is very clear with just this simple test that the exhaust system is responsible.
Some exhaust systems contain flexible couplings and may not require evaluation unless the exhaust system is damaged.
If you suspect the air conditioning system or drive belt, turn on the air conditioning system before performing the NERU test. If a noise occurs at a specific rpm, turn the air conditioning system off and on to see if the noise is connected to the air conditioning compressor or A/C system lines.
Results of the NERU test should be compared with the results of the road test to sort out vibrations and noises caused by the engine from those caused by the transmission, driveshaft or axle. If, during the road test, a vibration or noise occurs at a particular speed, try operating in another gear at the same speed. This changes the engine rpm and helps to sort out engine induced vibrations and noises. If it occurs at a particular rpm, use different gears to test at the same rpm at different road speeds. Turn the air conditioning system off and on at road speeds where noise occurs to isolate air conditioning system problems.
Drive Engine Run-Up Test (DERU)
CAUTION: Do not conduct this test for over 30 seconds, or without periodic driving or shifting to neutral to circulate transmission lubricant, otherwise, the transmission will overheat causing severe damage to the automatic transmission.
Set both the parking brake and service brake and take care to perform the test with enough space ahead of the vehicle to eliminate the possibility of an accident should the vehicle unintentionally lurch forward.
Put the transmission in D (drive) and run the engine up and down between idle and approximately 2000 rpm. Note the nature of any vibrations and noises and when these concerns occur in relation to engine rpm. This test is particularly good for examination of the exhaust system, and hanging keys on the tailpipe can serve as a "telltale" indicator.
The following worksheet is invaluable for recording customer comments as well as inspection and road test data.
Road Test Form
Road Test Quick Checks
24-80 km/h (15-50 mph): With light acceleration, a moaning noise is heard, and possibly a vibration is felt in the floorpan. 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 Pinpoint Test B.
Slow acceleration and deceleration: A shake is sometimes noticed in the steering wheel (3600)/steering column tube, seats, floorpan, trim panels 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 Pinpoint Test A.
At road speed: A vibration is felt in the floorpan or seats with no visible shake, but with an accompanying sound or rumble, buzz, hum, drone or booming noise. Coast with transmission control selector lever in NEUTRAL and engine idling. If vibration is still evident, it may be related to wheels, tires, front disc brake rotors (1125), rear brake drums (1126) wheel hubs (1104), wheel bearings (4000), driveshaft balance, rear axle universal joint ****** runout or transmission balance.
Refer to Pinpoint Test A.
0-High Speed: A vibration is felt whenever the engine reaches a particular rpm. It will disappear in NEUTRAL coast. The vibration can be duplicated by operating the engine at the problem rpm while the vehicle is parked. 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 Pinpoint Test D.
Road Conditions
The type of road and its surface condition are important factors in the road test. A smooth asphalt road that allows driving over a range of speeds is best. The brushed concrete road surface found on many expressways and the coarse aggregate sometimes found in concrete can mask many vehicle noises and make NVH diagnosis difficult.
If the 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 condition of the road surface and not the vehicle. If possible, try to test on the same type of surface. In this case, a smooth asphalt road may not be the best.
Vehicle Preparation
Check and verify if vehicle is equipped with original equipment (OE), type, size and brand wheels and tires. If non-original equipment (OE) wheels and or tires are installed, it may be necessary to substitute original equipment (OE) level tire/wheel assemblies to eliminate this factor before proceeding with the NVH diagnosis. Check and verify that ride height of vehicle has not been modified.
Check and set tire pressure.
Unlock the front hubs and back up approximately 20 feet to make sure of hub disengagement if the vehicle is a 4x4.
Remove any externally mounted accessories such as luggage racks, or magnetic base or the antenna which may cause wind noise that interferes with NVH diagnosis.
Use a tachometer.
Note the fuel level. Some vehicles change in their response to various excitations when the fuel level changes. If the customer mentions that the concern does not occur all the time, this might be a factor.
Try to duplicate the conditions with the customer present, particularly the speed and throttle operation. It is not uncommon to find concerns which the customer didn't notice so it is important to identify the specific concern causing the complaint.
Find the speed where the concern is most severe.
Turn the air conditioning system off and on to isolate air conditioning system impact on the noise. Accelerate gently through this speed to a few mph above it and then coast back down a few mph below it and note if the concern changes character when driving through or coasting down.
Repeat this procedure if necessary to get a feeling for the behavior. Then drive about five mph above the speed, put the transmission in neutral and coast down. Note any change in behavior.
Try "floating" the driveline by backing off slightly on the throttle at the problem speed. The idea is to unload the axle gears and the universal joints as much as possible. This test is difficult to master and sometimes it helps to test on a slight downgrade so that gravity is counteracting the aerodynamic drag.
If the concern does not change in all these modes of operation, the cause may well be driveline imbalance since the imbalance is not changed by the throttle position.
If there is a distinct change in the character or intensity between the drive and coast modes of operation, the concern is not likely imbalance but is most likely due to the axle or the universal joints since they are sensitive to the load on the driveline. (The axle pinion gear teeth are machined on two separate machines. One machine does the drive side of the teeth, another does the coast side. Hence there can be a great difference in performance between driving and coasting in gear.) If the noise and/or vibration goes away when the driveline is "floated" or when coasting through the speed range in neutral, the diagnosis is strengthened. Driveline imbalance does not go away in a neutral coast, but axle and joint concerns may.
To become familiar with the symptoms of imbalance and to determine if driveline imbalance exists on the vehicle, intentionally imbalance the driveline. This can be done by installing three hose clamps with ***** heads aligned on the rear of the driveshaft. Test drive the vehicle again. If the same vibration is still present but now intensified, the concern is driveline imbalance. If a new vibration is now present as a result of the intentional imbalance, the original condition would not be caused by driveline imbalance.
Hoist Test
After a road test, but only after a road test, it is sometimes useful to do a similar test on a hoist. Use an axle hoist, not a frame hoist. An axle hoist will not change the driveline angles. If only a frame hoist is available, axle stands should be used.
Elevate the rear wheels slightly. Check to make sure that both are turning, and run the engine up with the vehicle in gear.
Explore the speed range of interest using the drive/cruise/coast/float tests as described under Vehicle Preparation.
A coast down in neutral should also be conducted. If the vehicle is free of vibration when operating at a steady indicated speed and behaves very differently in drive and coast, an axle concern is likely.
A test on the hoist may produce different vibrations and noises than a road test because of the effect of the hoist on the rear axle. It is not unusual to find vibrations on the hoist that were not found in the road test and in most instances they may be ignored. Similarly, some problems may be apparent only on smooth asphalt roads. If the condition that was found on the road can be duplicated on the hoist, a great deal of time can be saved by doing experiments on the hoist.
========
E4OD Torque Converter:
If the shudder (or vibe) occurs;
a) during the 3-4 or 4-3 shift at HEAVY throttle,
or b at 40mph in 2, OD OFF, and OD, or c) at the same RPM in every gear, or d) coasting, cruising, or in R, or e) during extended light braking, then it is NOT TC clutch shudder;
The following is a list of common vehicle concerns that have been misdiagnosed as torque converter clutch shudder. For diagnosis of the following items, refer to the appropriate sections of the workshop manual and the Powertrain Control/Emissions Diagnosis manual (PCED).
Spark plugs - check for cracks, high resistance or broken insulators. P
lug wires.
Fuel injector - filter may be plugged.
Fuel contamination - engine runs poorly.
EGR valve - valve may let in too much exhaust gas and cause engine to run lean.
Vacuum leak - engine will not get correct air/fuel mixture.
MAP sensor - improper air/fuel mixture.
HO2S sensor - too rich/lean air/fuel mixture.
Fuel pressure - may be too low.
Engine mounts -loose/damaged mounts can cause vibration concerns.
Axle joints - check for vibration
thank you miesk5. now if only it wasnt supposed to rain all week and then snow for a finally, i could start these tests. i printed all the pages on the ****** so i can read up on them during work. i feel nearly positive though that it is something to do with the transmission. it happens inconsistently but always near the end of a shift change or at low rpms when i add slight pressure to the gas. this only happens during driving, not in park postion or reverse or neutral. i did try the cruise control to see if it happened while that was on, it still happens.
yo numsleven,
YW,
It is lenghty, but that is what a Ford tech would do; figure on $99.00 or so just to get it on the road test, then add hourly charges.
Also Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.
Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.
Do Key On Engine Off (KOEO) portion first.
Look Codes up in my broncolinks.com site using the new Search function.
And Post em here according to:
KOEO
&
KOER
Also the Check Engine Light (CEL) comes on when the electronic engine control system is not working properly. The check engine warning indicator comes on briefly when the ignition switch lock cylinder is turned to ON, and should turn off when the engine starts. If the check engine warning indicator does not come on when the ignition switch lock cylinder is turned to ON or if it comes on while the vehicle is moving, the system is malfunctioning
If the CEL does not light up at all when starting it; then suspect that someone removed it
YW,
It is lenghty, but that is what a Ford tech would do; figure on $99.00 or so just to get it on the road test, then add hourly charges.
Also Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/page__pid__74587__mode__threaded
The engine temperature must be greater than 50° F for the Key On Engine Off (KOEO) Self-Test and greater than 180° F for the Key On Engine Running (KOER) Self-Test.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.
Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.
Do Key On Engine Off (KOEO) portion first.
Look Codes up in my broncolinks.com site using the new Search function.
And Post em here according to:
KOEO
&
KOER
Also the Check Engine Light (CEL) comes on when the electronic engine control system is not working properly. The check engine warning indicator comes on briefly when the ignition switch lock cylinder is turned to ON, and should turn off when the engine starts. If the check engine warning indicator does not come on when the ignition switch lock cylinder is turned to ON or if it comes on while the vehicle is moving, the system is malfunctioning
If the CEL does not light up at all when starting it; then suspect that someone removed it
I printed the pages out yesterday and have had enough time to just glance through during work. I have picked a cpl tests that should help. I did notice the trany box is leaking and if that's low on fluid it can cause the problem. It's a half bar short of being full on fluid. My profile has a few more things about the problems I am having.
Last edited by a moderator:
Krafty
New member
thats checking trans fluid level with engine and trans warm and running correct?
I would tackle fixing that leak before anything else.
I would tackle fixing that leak before anything else.
I started going through the list of procedures to determine the vibrating. When I jacked the truck up and spun the wheels, there was free play all around but there's about a 3inch section that while rotating the wheels there is a lot of free play than makes a loud click sound and the sound as if there is a loose chain inside the transmission. I know there isn't a chain there. The sound comes from the back side where I believe the torque converter is at. I don't know if this is a problem or if its normal. I didn't find any other area or part on the truck that could b making the vibration so I concluded it has to do with this.
yo,
It would be better to keep all noise related queastions in your original vibration post mainly so we know what year, engine, tranny/xfer case you have and what has been checked to date.
Could be he torque converter bolts or the transfsr case chain.
It would be better to keep all noise related queastions in your original vibration post mainly so we know what year, engine, tranny/xfer case you have and what has been checked to date.
Could be he torque converter bolts or the transfsr case chain.
yo,
E4OD Removal by Ian L (stangmata, stangmata50l, Bronco) at http://www.supermotors.net/registry/4089/20383
See more LINKs in my site @ http://www.broncolinks.com/index.php?index=63
Scroll down to; Removal
E4OD Removal by Ian L (stangmata, stangmata50l, Bronco) at http://www.supermotors.net/registry/4089/20383
See more LINKs in my site @ http://www.broncolinks.com/index.php?index=63
Scroll down to; Removal
How can you tell when your automatic hubs ARE going bad? I just want to be sure before I go pick up the warn manual hubs. Right now they seem fine. Lock in and out with no problem but I'm wondering if there's a way to tell if they are trying to engage while I'm driving, not pushing the button to go to 4x4.
