Bad Vibration at 70-80 MPH

[buzzard]

Anybody else have terrible vibrations in this speed range? Did it with the balanced and re-balanced Pirelli's & now with brand new Revo 2's so it ain't the tires. I've had mine in three separate times, two of which service tech rode along saying they felt it, but none have a solution to fix. The last dealership rebuilt the tranny and in turn said the vibration was fixed, but it's not.

[Tylus]

need more info about your Expy

rim size?

rubber size?

tire brand and model?


also, it sounds stupid, but remove your wheels and check the wheel studs. From the Factory there is sometimes a little retainer clip left on 1-2 studs.

That tiny little bit of metal is enough to cause an imbalance.




also, please retorque the wheels on. it sounds stupid, but overtorquing the wheels can easily cause this vibration...kinda similar to the clips I mentioned above.



btw, torque value is 150 ft-lbs.




and does the Expy do it at 70-80 mph with O/D turned off? or only when in Overdrive? you might have a out of balance driveshaft

[5.4 Shelby]

Could your drive shaft have gotten turned when re-installing it after the tranny rebuild? The driveshaft is balanced for a certain position relative to the tranny. If they rotated it, it could be out of balance.

[gpfarrell]

The wheelstud clips are an idea, but it should have vibrated since day 1 if that's the problem.

I'd be inclined to look at driveshaft & u-joints. Remember driveshaft rpms depend on wheel speed, not engine speed, so the OD shouldn't make a difference.

If the OD does make a difference then the issue is probably engine-speed related instead of driveshaft related... but your symptoms seem to match vehicle speed not engine rpms.

[berry1234]

TSB 08-24-2

12/08/08
VIBRATION DIAGNOSTICS - STEERING WHEEL
NIBBLE - TIRE WHEEL RUNOUT AND BALANCE

FORD:
2005 Excursion, Explorer Sport Trac
2005-2008 Escape, Expedition, Explorer,
F-150, F-Super Duty, Ranger
2006-2008 F-53 Motorhome Chassis
2007-2008 Explorer Sport Trac

LINCOLN:
2005-2008 Navigator
2006-2008 Mark LT

MERCURY:
2005-2008 Mariner, Mountaineer

This article supersedes TSBs 07-11-3, 07-10-8, and 07-4-5 to update the Part List and Service procedure.
ISSUE
Various Ford, Mercury and Lincoln vehicles may exhibit a vibration / steering wheel nibble above 50 MPH (80 Km/h) which may be associated to a wheel and tire vibration.

ACTION
Follow the Service Procedure steps to correct the condition.

SERVICE PROCEDURE

The following revisions have been made. The road test has been simplified to include 15 minutes of driving rather than a 20 mile test drive. The requirement to bring an assistant along on the road test has been eliminated. Recordings should be made using the vibration analyzer and then review recordings following the test drive. The step to inspect the Integrated Wheel Ends (IWE) has also been eliminated.
1. Long term temporary flat spotting can develop when a vehicle is stored without driving. Some initial tire and wheel vibration issues (such as flat spotting) will correct themselves after the tires have been in service for 200 miles (320 km). Confirm vehicle tires have been in service a minimum of 200 miles (320 km) to remove long term temporary flat spotting. Do not continue with this procedure if tires do not meet this requirement.

2. Refer to Workshop Manual (WSM), Section 100-04 to determine if a wheel and tire speed (9-14.5 HZ) vibration is present.

a. If the vibration is wheel and tire speed proceed Step 3.

b. If not, follow the diagnostics provided in the WSM, Section 100-04.

NOTE THE VEHICLE SHOULD BE DRIVEN 15 MINUTES TO REMOVE TEMPORARY FLAT SPOTTING. SHORTER TEST DRIVES WILL RESULT IN INACCURATE RUN OUT OR ROAD FORCE(R) READINGS. IF THE VIBRATION GOES AWAY DURING THE TEST DRIVE, THE CONCERN IS DUE TO TEMPORARY TIRE FLAT SPOTTING WHICH IS A NORMAL TIRE CONDITION. NO FURTHER DIAGNOSIS OR REPAIRS SHOULD BE PERFORMED.

3. If tire and wheel vibration persists after the 15 minute road test, then complete wheel and tire radial run-out / Road Force® component test in the WSM, Section 204-04 to match mount and/or balance tire and wheel assemblies.

NOTE THE MATCH MOUNTING PROCEDURE IS MORE EFFECTIVE WHEN USING HUNTER ROAD FORCE(R) MEASUREMENT EQUIPMENT. THERE IS A WEBSITE AVAILABLE (WWW.G5P9700.COM) TO LOCATE THE NEAREST FACILITY THAT HAS THIS TYPE OF EQUIPMENT. ONLY USE A STANDARD BALANCER AND MANUALLY CHECK RUN OUT WHEN ABSOLUTELY NECESSARY.

NOTE WHEEL-TO-HUB OPTIMIZATION WHEEL-TO-HUB OPTIMIZATION IS IMPORTANT. CLEARANCE BETWEEN THE WHEEL AND HUB CAN BE USED TO OFFSET OR NEUTRALIZE THE ROAD FORCE(R) OR RUN-OUT OF THE WHEEL AND TIRE ASSEMBLY. FOR EVERY 0.001" (0.0254 MM) OF WHEEL-TO-HUB CLEARANCE, THE ROAD FORCE(R) CAN BE AFFECTED BETWEEN 1-3 LBS (0.45-1.36 Kg). DEPENDING ON THE TIRE STIFFNESS.

4. When installing tire and wheel assemblies follow WSM, Section 204-04, Wheel-to-Hub Optimization procedure. There are unique procedures for single rear wheel vehicles, dual rear wheels vehicles, and vehicles with conical shaped lug nuts.

NOTE THE SPARE TIRE SHOULD NOT BE USED AS A REPLACEMENT TIRE.

F-150 and MARK LT ONLY - If the vibration still persists continue to Step 5.
5. Perform the following based on remaining symptom:

a. If vibration still exists at 50-60 MPH (80-97 Km/h) (9-11 Hz), condition may be due to vehicle sensitivity or road inputs. Obtain Frame Damper Kit and refer to the instruction sheet included in the kit for installation.

NOTE THE DAMPER KIT WILL NOT HELP A STEERING WHEEL NIBBLE CONDITION OR A DRIVELINE VIBRATION (25-45 HZ).

NOTE CERTAIN VEHICLES ARE ALREADY EQUIPPED WITH THE FRAME DAMPER

[buzzard]

It's a 2008 4x4 EB Expedition with factory 18" rims. It had 255/70/18 Pirelli's & now it has 275/65/18 Bridgestone Revo 2's. It rides smooth as silk up to 60 then gradually worse and worse into the 80's. Having gone through several tire balances, I'm inclined to believe it's drivetrain related, but it's not the way the driveshaft was re-installed after the tranny overhaul because it vibrated equally as bad before it went in two weeks ago. At this point I'm so exasperated (not to mention embarrassed to even have anyone ride in it) with this vehicle and all it's problems, I'm inclined to drop it off at a dealership and tell them to keep it till something is really done to correct the concern.

FWIW, when it was in for the tranny rebuild, they gave me a '10 F150 that was rough as hell at lower speeds, but floated on air between 70 and 90. I was amazed how smoothly that truck rode at higher speeds. If my Expy rode half as nicely at those speeds I'd be elated.

Tomorrow I'll have the wheels re-balanced again and check for any foreign objects on the studs.

berry, thanks for the info. I haven't seen that TSB, so I'll call my service guy tomorrow and inquire as to what he knows about it. Although anything is possible, I'll be really surprised if their shop doesn't know about that TSB because, during the week+ they had my truck, the service manager informed me that he was going to review all associated TSB's.

[RRranch]

Are you inflating the tires to the recommended pressure on the door sticker or to the max pressure on the tire. You should go by the door sticker.

Putting the driveshaft on different makes absolutely no difference. It's balanced as a unit by itself. Not on the truck.

If the tech used the vibration analzer he should have been able to find the vibration. I went to the vibration analysis school for Ford and GM and it's so easy to find these things it's not even funny.

What I can say from experience is that if your wheels are torqued right, balanced, that retainer clip makes no difference either, and inflated right then it's probably rear end on a new truck. At Gm I could almost always blame it on a bad pinion bearing. At Ford it was the same thing or on a lot of them it was just a heat shield underneath too that would hit just the right frequency at 70-80 mph to get set off vibrating in an audible range. I'd have to feel it to tell you. If you have an aluminum rear gear housing I'd suspect that first and do a further diagnosis on it. If you are near Lubbock I'd be happy to take a ride with you and help figure it out. I don't work for Ford anymore but I still really hate vibrations like this.
I found a good one on my new 94 F350 yesterday. Just added it to the list of other things the dealer did wrong for it's last owner. 2 out of the 4 bolts holding my rear fuel tank skid plate were loose and one was missing. No more vibration now.

[berry1234]

If the vibration was exactly the same with the old tires and the new tires I would bet money it's not them. I would guess driveshaft, rear end, tranny. Does the vibration progressively get worse as you speed past 80mph? Does the whole car shake or just the steering wheel?

[Passin Thru]

HMMM! My 97 PSD does it at 130 MPH. Its probably unbalanced driveline. Thsy can be removed and balanced.

[buzzard]

RRanch, great info. This is the kind of ammo I need when it goes back in. Oh and thanks for the offer, but I'm in S. Texas.

berry, a little more info. The vibration isn't too bad going up and is at its absolute worst after a fairly hard acceleration to 80 or 85 then quickly letting off the gas pedal. As the speed drops through low 80's and all the way through the 70's it sometimes vibrates like a bucking horse and other times vibrates very noticeably. And to answer your question, the entire vehicle shakes, not just the steering wheel.

I really cannot believe the techs cannot find the root problem. Regardless, it's going in next week and staying till something is physically done. There's no excuse for such poor ride quality in a relatively expensive vehicle.

[RRranch]

Now it's really sounding like a ring and pinion to me. Actually the ring gear not shimmed right. Or pinion too loose on teh ring gear. The part about backing off the throttle making it worse makes me suspect that. I would pull the back tires off and drop the driveshaft then turn the pinion by hand. See if it feels gritty or if you can move the pinion up and down at all. It's hard to describe what it is supposed to feel like on here.

Also pinion bearing noise/vibration usually starts at about the speeds you are having problems at and as it gets worse gets more constant and at lower speeds.

[berry1234]

I would either take it to a new dealer or talk to the manager and have ask him if he can not fix it, can he call ford and have an Engineer come out. They will do this. Most techs are just are not interested in hunting down something that is not plainly obvious.

[Moto Mel]

Before you take it to any dealer you should ask if they have a tech that has been to the vibration analysis school and if they have the diagnostic tool needed to isolate the problem. Some dealers may have the tool but it's broken or they don't have a tech that is trained in its proper use. You should also have any and all TSBs relating to the issue with you when you see the service manager. If you are so inclined, you could get under the truck and see if there is any play in the pinion bearing/gears by trying to move the driveshaft foreward and rearward for checking the pinion bearing endplay, then block the wheels if the truck is on an incline, put it in neutral and try to turn the driveshaft. If there is more than the slightest movement there is a problem with the gear settings. If you have owned the truck since new you should know if the rear has been apart or not, if you bought the truck as a demonstrator or used unit may have been apart and repaired by a tech that didn't know what he was doing.
Hopefully all this info that you have gleaned here will help you.
Let us know the fix when you get it repaired.

[khangmai]

It could be a steel belt separation in one of the tires or a tire was out of round or a cracked rim.

[Moto Mel]

.[/quote]

berry, a little more info. The vibration isn't too bad going up and is at its absolute worst after a fairly hard acceleration to 80 or 85 then quickly letting off the gas pedal. As the speed drops through low 80's and all the way through the 70's it sometimes vibrates like a bucking horse and other times vibrates very noticeably. And to answer your question, the entire vehicle shakes, not just the steering wheel.

I really cannot believe the techs cannot find the root problem. Regardless, it's going in next week and staying till something is physically done. There's no excuse for such poor ride quality in a relatively expensive vehicle.
__________________
Jim



I have just reread your posts on this problem and I think you have given us the best clue as to the cause of your problem. I had nearly the same symptoms. Check your universal joints and the cardan joint . I believe your problem is there. I am also adding Ford's service info for driveline testing. READ PARAGRAPH 5 CAREFULLY. There is probably much more info than you need but use what is useful for you. Also I am not able to get the drawings to post.

SECTION 205-00: Driveline System — General Information

2000 Expedition/Navigator Workshop Manual

DIAGNOSIS AND TESTING

---

Driveline System

****** name=tps_proctitle content="Driveline System">

Special Tool(s)

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1268A.gif~gen~ref.gif[/IMG]	Clamp Plate, Driveshaft 205-320 (T92L-4851-C)
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1348A.gif~gen~ref.gif[/IMG]	Gauge, Clutch Housing 308-021 (T75L-4201-A)
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1257A.gif~gen~ref.gif[/IMG]	Holding Fixture, Drive Pinion Flange 205-126 (T78P-4851-A)
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1267A.gif~gen~ref.gif[/IMG]	Runout Gauge, Drive Pinion Flange 205-319 (T92L-4851-B)
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1214A.gif~gen~ref.gif[/IMG]	Dial Indicator Gauge with Holding Fixture 100-002 (TOOL-4201-C) or equivalent
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1266A.gif~gen~ref.gif[/IMG]	Dial Indicator with Holding Fixture 100-D002 (D78P-4201-B) or equivalent
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ST1863A.gif~gen~ref.gif[/IMG]	Gauge, Differential (Traction-Lok) 205-385 (T97T-4205-B)

Inspection and Verification
Certain axle noise or vibration symptoms are also common to the engine, transmission, wheel bearings, tires, and other parts of the vehicle. For this reason, be sure that the cause of the trouble is in the axle before disassembling, adjusting or repairing the axle. For additional information, refer to Section 100-04 .
Certain driveshaft vibration symptoms are common to the front engine accessory drive (FEAD), the engine, transmission or tires. Be sure the cause of the concern is the driveshaft before repairing or installing a new driveshaft. For additional information, refer to Section 100-04 .
Certain symptoms may be caused by Traction-Lok® differentials (4026). Check the vehicle certification label and axle identification tag to determine the type of differential. For additional information, refer to Section 100-01 .

Noise Acceptability
NOTE: A gear-driven unit will produce a certain amount of noise. Some noise is acceptable and audible at certain speeds or under various driving conditions such as a newly paved blacktop road. Slight noise is not detrimental to the operation of the axle and is considered normal.
With the Traction-Lok® differential axle, slight chatter noise on slow turns after extended highway driving is considered acceptable and has no detrimental effect on the locking axle function.

Universal Joint (U-Joint) Inspection
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ani_caut.gif~gen~ref.gif[/IMG] WARNING: The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.
Place the vehicle on a frame hoist and rotate the driveshaft (4602) by hand. Check for rough operation or seized U-joints. Install a new U-joint if it shows signs of seizure, excessive wear, or incorrect seating. For additional information, refer to Section 205-01 .

Inspection For Bent Rear Axle

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ani_caut.gif~gen~ref.gif[/IMG] WARNING: The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.

1. Raise and support the vehicle. For additional information, refer to Section 100-02 . Allow the rear axle to be freely suspended.

1. Use white chalk or paint to mark a vertical line on the center of each rear tire.

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=GE0781A.gif~gen~ref.gif[/IMG]

1. Adjust both wheels so that the markings face the front of the vehicle. With a tape measure, measure the distance between the marks and record this reading (front reading).

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=A0012007.gif~gen~ref.gif[/IMG]

1. Rotate the rear wheels so the markings are directly underneath the vehicle. Measure the distance between the marks and record this reading (bottom reading).

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=A0012008.gif~gen~ref.gif[/IMG]

1. Rotate the rear wheels so the markings face the rear of the vehicle. Measure and record the distance between the marks (rear reading).

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=A0012009.gif~gen~ref.gif[/IMG]

1. Compare the front and the rear readings (Steps 3 and 5) to find the toe-in or toe-out condition.
   • Toe-in occurs when the front measurement is less than the rear measurement.
   • Toe-out occurs when the rear measurement is less than the front measurement.

1. To determine camber, find the average of the front and the rear measurements (Steps 3 and 5). Subtract the bottom reading (Step 4) from this number.
   Positive (+) camber is when the bottom reading is less than the average of the front and rear readings. Negative (-) camber is when the bottom reading is greater than the average of the front and rear readings.

1. The results of the calculations in Steps 6 and 7 must conform to the following specifications:
   Toe-in: 0 — 1/16 inch.
   Toe-out: 0 — 3/16 inch.
   Camber: 0 ± 5/32 inch.
   If the axle housing does not meet these specifications, a new axle housing must be installed. Refer to Section 205-02A or Section 205-02B .

1. After the axle housing has been installed, repeat Steps 2 through 7.

Analysis of Leakage

Clean up the leaking area enough to identify the exact source. An axle leak can be caused by the following:

• Axle lubricant level is too high.
• Worn or damaged axle shaft seals or differential seals.
• Differential housing is cracked.
• Flange yoke seal is worn or damaged.
• Pinion flange is scored or damaged.
• Axle cover is not sealed.
• Vent is plugged.

Repair the axle as necessary. Make sure the axle lubricant is at the correct level. For additional information, refer to Specifications if this section.
Axle Vent
NOTE: If a plugged vent cannot be cleared, install a new one.
A plugged vent will cause excessive seal lip wear due to internal pressure buildup. If a leak occurs, check the vent. Make sure the vent hose is not kinked. Remove the hose from the vent nipple and clear the hose of any foreign material. While the hose is removed, pass a length of mechanics wire or a small diameter Allen wrench in and out of the vent to clean it. Connect the hose when done.
Flange Yoke Seal

Leaks at the axle drive pinion seal originate for the following reasons:

• Seal was not correctly installed.
• Poor quality seal journal surface.

Any damage to the seal bore (dings, dents, gouges, or other imperfections) will distort the seal casing and allow leakage past the outer edge of the axle drive pinion seal.
The axle drive pinion seal can be torn, cut, or gouged if it is not installed carefully. The spring that holds the axle drive pinion seal against the pinion flange may be knocked out and allow leakage past the lip.
The rubber lips can occasionally become hard (like plastic) with cracks at the oil lip contact point. The contact point on the pinion flange may blacken, indicating excessive heat. Marks, nicks, gouges, or rough surface texture on the seal journal of the pinion flange will also cause leaks.
Axle drive pinion seal wear 1.27 mm (0.050 inch) or greater is considered excessive.
A new pinion flange must be installed if any of these conditions exist.
Metal chips or sand trapped at the sealing lip may also cause oil leaks. This can cause a wear groove on the pinion flange and heavy pinion seal wear.
When a seal leak occurs, install a new seal and check the vent and the vent hose to make sure they are clean and free of foreign material.
Axle Shaft Seals
Axle shaft oil seals (3254) are susceptible to the same kinds of damage as axle drive pinion seals if incorrectly installed. The seal bore must be clean and the lip handled carefully to avoid cutting or tearing it. Axle shaft journal surface must be free of nicks, gouges, and rough surface texture.
Differential Seals
For additional information on differential seals, refer to Section 205-02A or Section 205-02B for the rear axle or Section 205-03 for the front axle.

Analysis of Vibration
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ani_caut.gif~gen~ref.gif[/IMG] WARNING: A vehicle equipped with a Traction-Lok® differential will always have both wheels driving. If only one wheel is raised off the floor and the rear axle is driven by the engine, the wheel on the floor could drive the vehicle off the stand or jack. Be sure both rear wheels are off the floor.
Few vibration conditions are caused by the front or rear axle. On a vibration concern, follow the diagnosis procedure in Section 100-04 unless there is a good reason to suspect the axle.
Tires
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ani_caut.gif~gen~ref.gif[/IMG] WARNING: Do not balance the wheels and tires while they are mounted on the vehicle. Possible tire disintegration/differential failure could result, causing personal injury/extensive component damage. Use an off-vehicle wheel and tire balancer only.
Most vibration in the rear end is caused by tires or driveline angle.
Vibration is a concern with modern, high-mileage tires if they are not "true" both radially and laterally. They are more susceptible to vibration around the limits of radial and lateral runout of the tire and wheel assembly. They also require more accurate balancing. Wheel and tire runout checks, truing and balancing are normally done before axle inspection. For additional information, refer to Section 204-04 .
Driveline Angle
Driveline angularity is the angular relationship between the engine crankshaft (6303), the driveshaft, and the rear axle pinion. Factors determining driveline angularity include ride height, rear spring (5560), and engine mounts.
Driveline Angle

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=A0014659.gif~gen~ref.gif[/IMG]

Item	Description
1	Bottom of the frame
2	Engine crankshaft centerline
3	Engine angle
4	Driveshaft and coupling shaft centerline
5	Driveshaft and coupling shaft angle
6	Rear axle pinion centerline
7	Axle pinion angle

An incorrect driveline (pinion) angle can often be detected by the driving condition in which the vibration occurs.

• A vibration during coasting from 72 to 56 km/h (45 to 35 mph) is often caused by a high axle pinion angle.
• A vibration during acceleration, from 56 to 72 km/h (35 to 45 mph) may indicate a low pinion angle.

When these conditions exist, check the driveline angles as described in the General Procedures portion of this section.
If the tires and driveline angle are not the cause, carry out the NVH tests to determine whether the concern is caused by a condition in the axle. Refer to Section 100-04 .
Universal Joint (U-Joint) Wear
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ani_caut.gif~gen~ref.gif[/IMG] WARNING: The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.
Place the vehicle on a frame hoist and rotate the driveshaft by hand. Check for rough operation or seized U-joints. Install a new U-joint if it shows signs of seizure, excessive wear, or incorrect seating. Refer to Section 205-01 .
Wheel Hub or Axle Flange Bolt Circle Runout

NOTE: The brake discs must be removed to carry out all runout measurements.

1. Position the special tool perpendicular to the wheel hub or axle flange bolt, as close to the hub or flange face as possible. Zero the indicator to allow the pointer to deflect either way.

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=DE2879A.gif~gen~ref.gif[/IMG]

1. Rotate the hub or flange until the next bolt is contacted. Record the measurement and continue until each bolt is checked. The difference between the maximum and minimum contact readings will be the total wheel hub or axle flange bolt pattern runout. The runout must not exceed 0.38 mm (0.015 inch).

Pilot Runout

1. Position the special tool as close to the hub or axle flange face as possible. Zero the indicator to allow the pointer to deflect either way.

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=DE2880A.gif~gen~ref.gif[/IMG]

1. Rotate the hub or flange one full turn and note the maximum and minimum readings. The difference between the maximum and minimum readings will be the total pilot runout. Pilot runout must not exceed 0.15 mm (0.006 inch).

Wheel Hub or Axle Flange Face Runout

NOTE: If the axle shaft assembly is removed, check runout of the shaft itself. The forged (unmachined) part of the shaft is allowed to have as much as 3.0 mm (0.120 inch) runout. This alone will not cause a vibration condition.

1. Position the special tools on the wheel hub or axle flange face, as close to the outer edge as possible. Zero the indicator to allow the pointer to deflect either way.

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=DE2881A.gif~gen~ref.gif[/IMG]

1. Rotate the hub or flange one full turn and note the maximum and minimum readings. The difference between the maximum and minimum readings will be the total face runout. The runout must not exceed 0.254 mm (0.010 inch).

Drive Pinion Stem and Pinion Flange
Check the pinion flange runout when all other checks have failed to show the cause of vibration.
One cause of excessive pinion flange runout is incorrect installation of the axle drive pinion seal. Check to see if the spring on the seal lip has been dislodged before installing a new ring gear and pinion.
Halfshafts, Front Wheel
NOTE: New constant velocity (CV) joints must not be installed unless disassembly and inspection reveals unusual wear. For additional information, refer to Section 205-04 .

NOTE: Inspect the boots for indentations ("dimples") in the boot convolutions. Indentations must be removed.

• Inspect the boots for evidence of cracks, tears, or splits.
• Inspect the underbody for any indication of grease splatter near the boots outboard and inboard locations. This is an indication of boot/clamp damage.

Axle Noise
NOTE: Before disassembling the axle to diagnose and correct gear noise, eliminate the tires, exhaust, trim items, roof racks, axle shafts (4234) and wheel bearings as possible causes. Follow the diagnostic procedures. For additional information, refer to Section 100-04 .
The noises described as follows usually have specific causes that can be diagnosed by observation as the unit is disassembled. The initial clues are the type of noise heard during the road test.
Gear Howl and Whine

Howling or whining of the ring gear and pinion is due to an incorrect gear pattern, gear damage or incorrect bearing preload.
Bearing Whine
Bearing whine is a high-pitched sound similar to a whistle. It is usually caused by worn/damaged pinion bearings, which are operating at driveshaft speed. Bearing noise occurs at all driving speeds. This distinguishes it from gear whine which usually comes and goes as speed changes.
As noted, pinion bearings make a high-pitched, whistling noise, usually at all speeds. If however there is only one pinion bearing that is worn/damaged, the noise may vary in different driving phases. New pinion bearings must not be installed unless scoring or damage is found or there is a specific pinion bearing noise. A worn/damaged bearing will normally be obvious at disassembly. Examine the large end of the rollers for wear. If the pinion bearings original blend radius has worn to a sharp edge, a new pinion bearing must be installed.
NOTE: A low-pitched rumble normally associated with a worn/damaged wheel bearing can be caused by the exterior luggage rack or tires.
A wheel bearing noise can be mistaken for a pinion bearing noise. On 4x2 vehicles, check the wheel bearing for a spalled cup, and spalled/damaged rollers. Install a new wheel bearing if any of these concerns are detected.
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=DE1352A.gif~gen~ref.gif[/IMG]
If the wheel bearing is damaged, the roller surface on the axle shaft may also be damaged. Install a new axle shaft if any damage is detected.
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=GE0790A.gif~gen~ref.gif[/IMG]
On 4x4 vehicles, check the wheel bearing for rotating smoothness and end play. Install new wheel bearings as required.
Chuckle
Chuckle that occurs on the coast driving phase is usually caused by excessive clearance between the differential gear hub and the differential case bore.
Damage to a gear tooth on the coast side can cause a noise identical to a chuckle. A very small tooth nick or ridge on the edge of a tooth can cause the noise.
Clean the gear tooth nick or ridge with a small grinding wheel. If the damaged area is larger than 3.2 mm (1/8 inch), install a new gearset.
To check the ring gear and pinion, remove as much lubricant as possible from the gears with clean solvent. Wipe the gears dry or blow them dry with compressed air. Look for scored or damaged teeth. Also look for cracks or other damage.
If either gear is scored or damaged badly, a new ring gear and pinion must be installed.
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=GE1438A.gif~gen~ref.gif[/IMG]
If metal has broken loose, the axle housing must be cleaned to remove particles that will cause damage. At this time if any other damaged parts are found in the axle housing, new parts must also be installed.
Knock
Knock, which can occur on all driving phases, has several causes including damaged teeth or gearset.
[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=GE0793A.gif~gen~ref.gif[/IMG]

In most cases, one of the following conditions will occur:

1. A gear tooth damaged on the drive side is a common cause of the knock. This can usually be corrected by grinding the damaged area.

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=GE0792A.gif~gen~ref.gif[/IMG]

1. NOTE: Measure the end play with a Dial Indicator Gauge with Holding Fixture and not by feel.
   The knock is also caused by excessive end play in the axle shafts. Up to 0.762 mm (0.030 inch) is allowed in semi-float axles. The frequency of the knock will be less because the axle shaft speed is slower than the driveshaft.

Clunk
Clunk is a metallic noise heard when the automatic transmission is engaged in REVERSE or DRIVE. The noise may also occur when throttle is applied or released. It is caused by backlash somewhere in the driveline or loose suspension components; it is felt or heard in the axle. Refer to Total Backlash Check in this section.
Additionally, clunk may be heard upon initial drive-away. This occurs as engine torque shifts vehicle weight, forcing changes in driveline angles, preventing the driveshaft slip-yoke from sliding on the output shaft. To correct this condition, lubricate the slip-yoke splines. For additional information, refer to Section 205-01 .

Total Backlash Check

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=ani_caut.gif~gen~ref.gif[/IMG] WARNING: The electrical power to the air suspension system must be shut off prior to hoisting, jacking or towing an air suspension vehicle. This can be accomplished by turning off the air suspension switch. Failure to do so can result in unexpected inflation or deflation of the air springs, which can result in shifting of the vehicle during these operations.

1. Raise and support the vehicle. For additional information, refer to Section 100-02 .

1. Remove the driveshaft. For additional information, refer to Section 205-01 .

1. Install the special tool.
   • Clamp a rigid bar or pipe to the tool. Clamp the other end of the bar or pipe to the frame or a body member in order to prevent movement of the pinion flange.

[IMG]file:///C:/TSO/tsocache/MEL-PC_5744/SYJ~us~en~file=DE1353B.gif~gen~ref.gif[/IMG]

1. Lower the vehicle so that one rear wheel is resting on a wheel chock to prevent it from turning. The other rear wheel will be used to measure total rear axle backlash.

1. Rotate the free wheel slowly, by hand, until the feeling of driving the rear axle is encountered. Place a mark on the side of the tire, 305 mm (12 inches) from the center of the wheel, with a crayon or chalk.

1. While holding the crayon or chalk against the tire, rotate the wheel slowly in the opposite direction until the feeling of driving the rear axle is encountered again.

1. Measure the length of the crayon or chalk mark on the tire.
   • If the length of the mark is 25.4 mm (1 inch) or less, the rear axle backlash is within allowable limits.
   • If the chalk mark is greater than 25.4 mm (1 inch), check for these conditions:
     • Elongation of the differential pinion shaft and holes in the differential case (4204).
     • Missing differential pinion thrust washer (4230) or differential side gear thrust washer (4228)
     • Galling of the differential pinion shaft (4211) and bore.
     • Excessive ring gear and pinion backlash. Follow the procedure for the type of rear axle to check backlash.

Axle Shaft Bearing Noise
Axle shaft bearing noise is similar to gear noise and differential pinion bearing whine. Axle shaft bearing noise will usually distinguish itself from gear noise by occurring in all driving modes (drive, coast, and float), and will persist with the transmission in NEUTRAL while the vehicle is moving at the speed in which the concern is occurring. If the vehicle makes this noise, remove the suspect axle shaft and install a new bearing and axle seal. Re-evaluate the vehicle for noise before removing any internal components.
Bearing Rumble
Bearing rumble sounds like marbles being tumbled. This condition is usually caused by a worn/damaged wheel bearing. The lower pitch is because the wheel bearing turns at only about one-third of the driveshaft speed. Wheel bearing noise also may be high-pitched, similar to gear noise, but will be evident in all four driving modes.

Look for page 2 of this information to follow.