Vibration between 50 & 70 mph

69mach1-395 said:

Is there a link to what ratio the rearend is?

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That's a good question. Be interesting to see that in the poll. I suspect not since the vibration is independent of whether I'm coasting or what gear the trans is in. Seems to be a range of driveshaft rpm that corresponds to approx 50-75 mph that peaks at 65 on my car but any rear end ratio would fall in that range. I have 3.15 gears in mine.

I have 3.55 Gears in mine/MT82.

Deysha contacted me today and told me she had escalated my case and a customer care rep would contact me. I think my dealer will help me with this, they just need a shove in the right direction..

I have put about 200 more miles on the car since i got it back from the dealership and it seems to be progressively and slowly getting worse.

I will post as i get more updates.

69mach1-395 said:

Is there a link to what ratio the rearend is?

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Mine is 3.55

My wife's car I believe is 3.15 as it is the EB non PP car. Hers is the worst. I think mine has it slightly and mine is a GT with PP so I have 3.73.

Blacklaw said:

They replaced my drive shaft twice and the half shafts, then the differential assembly. Nothing happened after the drive shaft replacement, but only when the differential assembly the replaced did the vibration stop.

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This was exactly my scenario up to the point of the differential replacement, which was completed today. Unlike yours, my vibration is still there. Kinda gives pause to the whole "it's the differential" thought process. Dealership is at a complete loss as to what to do now. Ford has given them no further guidance.
I now have a call into my CSM to discuss what can be done about replacing for another stang or buying me out.
Now this should be interesting.... they've been working on this for about 5 months now, only to be exactly where I was in April... so this shouldn't take any more than say a few months to get this settled! Man, this is frustrating.

billq said:

This was exactly my scenario up to the point of the differential replacement, which was completed today. Unlike yours, my vibration is still there. Kinda gives pause to the whole "it's the differential" thought process. Dealership is at a complete loss as to what to do now. Ford has given them no further guidance.
I now have a call into my CSM to discuss what can be done about replacing for another stang or buying me out.
Now this should be interesting.... they've been working on this for about 5 months now, only to be exactly where I was in April... so this shouldn't take any more than say a few months to get this settled! Man, this is frustrating.

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You guys are scaring me... they're putting a new DS in my car on Friday. Another poll might help- what fixed your problem- DS, diff, halfshafts, or nothing. Could also possibly be something in the transmission tailshaft.

speedfrk said:

You guys are scaring me... they're putting a new DS in my car on Friday. Another poll might help- what fixed your problem- DS, diff, halfshafts, or nothing. Could also possibly be something in the transmission tailshaft.

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That would be a good poll.

GT Pony said:

That would be a good poll.

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Done.

http://www.mustang6g.com/forums/showthread.php?t=32157

I don't believe there is a way to add a second poll to my original post; if someone knows how to do it, please let me know, and I will add it.

Got the car back from having the DS replaced. Vibration is now at a higher speed 70-75 but not gone. I guess I go back Monday and talk to the service manager. Pretty discouraging since I really wanted to like the car. The greasy hand prints all over the door didn't improve my mood either.

Just want to say 1 more time to try and help some one out.Had my drive shaft replaced and it still had the vibration. I put it on my lift and the paint match marks were not lined up on the drive shaft and pinion flange. I changed the clock position on the drive shaft to line up the marks and all is well. Easy to check, may be worth a few minutes to take a look.

888mustang said:

Just want to say 1 more time to try and help some one out.Had my drive shaft replaced and it still had the vibration. I put it on my lift and the paint match marks were not lined up on the drive shaft and pinion flange. I changed the clock position on the drive shaft to line up the marks and all is well. Easy to check, may be worth a few minutes to take a look.

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Are the paint marks only on the pinion flange or on the trans end also?

Only on the flange and rear of the drive shaft.

I do wonder if they are checking runout or just slapping new driveshafts in. If the pinion flange runout is out of tolerance, you can put all the new driveshafts in you want and it won't matter.

Copied from another forum...
From Ford Manual -Driveline Vibration

An analysis of driveline vibration can also be conducted using the Vibration Analyzer; follow the manufacturer's directions.

Driveline vibration exhibits a higher frequency and lower amplitude than does high-speed shake. Driveline vibration is directly related to the speed of the vehicle and is usually noticed at various speed ranges. Driveline vibration can be perceived as a tremor in the floorpan or is heard as a rumble, hum, or boom. Driveline vibration can exist in all drive modes, but may exhibit different symptoms depending upon whether the vehicle is accelerating, decelerating, floating, or coasting. Check the driveline angles if the vibration is particularly noticeable during acceleration or deceleration, especially at lower speeds. Driveline vibration can be duplicated by supporting the axle upon a hoist or upon jack stands, though the brakes may need to be applied lightly in order to simulate road resistance.

Raise the vehicle promptly after road testing. Use a twin-post hoist or jack stands to prevent tire flat-spotting. Engage the drivetrain and accelerate to the observed road test speed to verify the presence of the vibration. If the vibration is not evident, check the non-driving wheels with a wheel balancer to rule out imbalance as a possible cause. If required, balance the non-driving wheels and repeat the road test. If the vibration is still evident, proceed to Step 2.
Mark the relative position of the drive wheels to the wheel nuts. Remove the wheels. Install all the nuts in the reversed position and repeat the road speed acceleration. If the vibration is gone, refer to the tire and wheel runout procedure in Section 204-04 . If the vibration persists, proceed to Step 3.
Inspect the driveshaft for signs of physical damage, missing balance weight, undercoating, incorrect seating, wear and binding universal joints. Clean the driveshaft and install new universal joints or a new driveshaft if damaged. Check the index marks (paint spots) on the rear of the driveshaft and pinion flange. If these marks are more than one-quarter turn apart, disconnect the driveshaft and re-index to align the marks as closely as possible. After any corrections are made, recheck for vibration at the road test speed. If the vibration is gone, reinstall the wheels and road test. If the vibration persists, proceed to Step 4.
Raise the vehicle on a hoist and remove the wheels. Rotate the driveshaft by turning the axle and measure the runout at the front, the center, and the rear of the driveshaft with the indicator. If the runout exceeds 0.89 mm (0.035 inch) at the front or center, a new driveshaft must be installed. If the front and center are within this limit, but the rear runout is not, mark the rear runout high point and proceed to Step 5. If the runout is within the limits at all points, proceed to Step 7.

NOTE: Check the U-joints during re-indexing. If a U-joint feels stiff or gritty, install new U-joints.

Scribe alignment marks on the driveshaft and the pinion flange. Disconnect the driveshaft, rotate it one-half turn, and reconnect it. Circular pinion flanges can be turned in one-quarter increments to fine tune the runout condition. Check the runout at the rear of the driveshaft. If it is still over 0.89 mm (0.035 inch), mark the high point and proceed to Step 6. If the runout is no longer excessive, check for vibration at the road test speed. If vibration is still present, re-index the driveshaft slip yoke on the transmission output shaft one-half turn and road test the vehicle. If the vibration persists, proceed to Step 7.
Excessive driveshaft runout may originate in the driveshaft itself or in the pinion flange. To determine which, compare the two high points marked in Steps 4 and 5. If the marks are close together, within about 25 mm (1 inch), a new shaft must be installed and the vehicle road tested.

If the marks are on opposite sides of the driveshaft, the yoke or pinion flange is responsible for the vibration.


When installing a new pinion flange, the driveshaft runout must not exceed 0.89 mm (0.035 inch). When runout is within limits, recheck for vibration at road speed. If vibration persists, balance the driveshaft.

To balance the driveshaft, install one or two hose clamps on the driveshaft, near the rear. Position of the hose clamp head(s) can be determined by trial-and-error.
Mark the rear of the driveshaft into four approximately equal sectors and number the marks 1 through 4. Install a hose clamp on the driveshaft with its head at position No. 1.

Check for vibration at road speed. Recheck with the clamp at each of the other positions to find the position that shows minimum vibration. If two adjacent positions show equal improvement, position the clamp head between them.

If the vibration persists, add a second clamp at the same position and recheck for vibration.

If no improvement is noted, rotate the clamps in opposite directions, equal distances from the best position determined in Step 8. Separate the clamp heads about 13 mm (1/2 inch) and recheck for vibration at the road speed.

Repeat the process with increasing separation until the best combination is found or the vibration is reduced to an acceptable level.

Install the wheels and road test (vibration noticeable on the hoist may not be evident during the road test). If the vibration is still not acceptable, install a new axle driveline vibration damper first, if so equipped. If the vibration is still not acceptable, refer to Section 205-02A or Section 205-02B for differential case and ring gear runout checks

I got lucky. Finally.

I thought it might be a nice change to post a success story, so here goes...

History: My previous two Ford products had, or developed, vibrations. None of them were so bad that I couldn't drive them, but none of them were completely remedied. I spent well over $2,000 on the last Ranger, and still had the problem. This Mustang was by far the worst. So bad that I started to hate driving it.

Took the new Mustang to the dealership to fix the very significant vibration problem. Spoke with the service writer and described the circumstances of the vibration... entire car shimmies on glass-smooth roads at speeds over 65mph. He said they would look at it, but I couldn't wait for it. Gave me a loaner (C-max). Actually a very nice car for what it is, and surprising comfort, acceleration and handling. Probably a great commuter econobox for city driving.

Anyway, got a call that the car was fixed. Picked it up, and a few days later had the chance to get it out on the open road. Problem was still there. Slightly better, but still there. Blood pressure goes up, butt clenches, jaw starts to cramp from choking back all the expletives I wanted to yell. There's probably a medical term for this vehicle induced trauma.

In anger and desperation, I took the car to my mechanic and asked them to diagnose the problem so I could go back to the dealership with a specific complaint for them to address, since they couldn't handle a general complaint. Here comes the good news... even though the stealership SAID they had balanced all the tires, turns out that three of them were off by anywhere from 1/4 to 1/2 oz. When they got into a harmonic/sympathetic rotation, they started the highway conga line and the car shimmied. My guy recalibrated his dynamic balancing machine, and got them about as close to perfect as they could be.

Bottom line... SHIMMY/VIBRATION IS GONE! ... no thanks to the dealership.

888mustang said:

Only on the flange and rear of the drive shaft.

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I crawled under and checked- the 2 white lines are lined up. I was almost hoping they weren't...