Vibration between 50 & 70 mph

[FordTechOne]

I met with the Ford FSE this morning and he hooked up the vibration equipment to my car and we went driving. Interestingly, he doesn't try to deny that these cars have a driveline vibration. He said he has had 2 Mustang GT's as company cars and they both had it to some degree. One worse than the other and most people don't even notice it unless it is at the limit or higher. I liked his honesty but we were talking engineer to engineer at that point. At the speed where it is worst (60mph usually) it was reading .011 g's and the Ford spec is .025. So my car is less than half of the spec for the driveline frequency. But, he didn't claim that you couldn't feel it, he just said that he couldn't get it any better. He also told me the whole story about when he worked on it the first 2 times. The first time they actually pulled a driveshaft from another car on the lot and it made the vibration worse. Then they installed a new driveshaft and it was basically unchanged. Then they changed the pinion flange and it had more run out that the original flange, but it balanced with the DS much better. He said when you are balancing the DS, you are really balancing the DS, flange and part of the diff that is directly bolted to the flange. He also said that sometimes a car goes from horrible to really good with a just tiny weight added to the DS. So, the point is that it is black magic
My dilemma is- do I take the 100K extended warranty they are offering and call it a day or do I push on with the buyback. The vibration does annoy me, but he is shooting straight about the problem. I drove another new EB and GT on the lot, and they were both at least as bad as mine.
And, I demonstrated the clunk when going between rev/neut/drive and he checked and told them to order the front flange and nut.

Any vibration reading below .017g is barely perceivable to a human being. The fact that your car is reading .011g indicates that it's well within specification; there is nothing there that needs to be fixed. Any moving vehicle will have some degree of measurable vibration; vehicles with high durometer powertrain mounts, performance suspension, and low profile tires (like the Mustang) will always be worse. Getting a vehicle bought back for normal operation makes no sense at all.

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[jgedde]

I installed the Steeda differential bushings and the rear cradle bushing support kit. My vibration is now 95% gone. Can still very slightly feel it in steering wheel at 50 and hear it at close to 70, but the bass rumble at 60 MPH is all but gone.

Plus the car feels better too.

John

 

[speedfrk]

I installed the Steeda differential bushings and the rear cradle bushing support kit. My vibration is now 95% gone. Can still very slightly feel it in steering wheel at 50 and hear it at close to 70, but the bass rumble at 60 MPH is all but gone.

Plus the car feels better too.

John

Someone also posted that the Steeda IRS subframe braces made a big difference in his vibration level. They are cheap and easy to install so I may give them a try. Do the bushings change the ride harshness?

I want to test the car after they replace the front flange to see if that has any effect before I decide on pursuing the buyback or just working to get it as good as possible. Hopefully, they get that done this week.

 

[jgedde]

Someone also posted that the Steeda IRS subframe braces made a big difference in his vibration level. They are cheap and easy to install so I may give them a try. Do the bushings change the ride harshness?

I want to test the car after they replace the front flange to see if that has any effect before I decide on pursuing the buyback or just working to get it as good as possible. Hopefully, they get that done this week.

There is a slight increase in noise from the diff, nothing at all objectionable. Ride is a bit firmer but not in a bad way.

Handling is improved. Car feels more precis and controllable, although oversteer comes on more quickly than before and goes away on throttle lift easier.

I will also say this... My vibe problem was never as severe as others have reported. No miror shake. just feel in steering wheel and shifter at 50. Hear bass rumble (like a bass note from a bass box) at 60. I measure 45 Hz, which agrees nearly exactly with driveshaft speed sat 60 MPH with 27.7" diameter tires and 3.73 rear (calculate 45.26 Hz).

60 MPH * 1/3600 Hrs/sec * 63360 in/M * 1/(27.7 * pi) rotations/inch * 3.73 = 45.26 Hz

John

 

[MikeD1]

^^^ This stuff was the 1st excuse the FSE's gave for not fixing my car. They didn't even try anything, just pointed to the Steeda stuff & said 'it's modified and those parts could be causing the issue'.

As expected, removing all of it just made the issue worse & the FSE's were every bit as clueless with the suspension 'bone stock'.

So net is - yes, the Steeda stuff does work, it does not add to the vibration or make the ride uncomfortable, but Ford is looking for any excuse to NOT fix these cars and will use it as a scapegoat & delay tactic.

 

[Mr981]

^^^ This stuff was the 1st excuse the FSE's gave for not fixing my car. They didn't even try anything, just pointed to the Steeda stuff & said 'it's modified and those parts could be causing the issue'.

As expected, removing all of it just made the issue worse & the FSE's were every bit as clueless with the suspension 'bone stock'.

So net is - yes, the Steeda stuff does work, it does not add to the vibration or make the ride uncomfortable, but Ford is looking for any excuse to NOT fix these cars and will use it as a scapegoat & delay tactic.

Given the slow reaction to remedy the problem and the apparent cluelessness of the dealer network as a whole on this issue, your comment would seem to be accurate.
By itself, that would suggest the cost of a real fix for it is very significant, to the point where Ford would rather fight with individual owners, than get into the drill of bringing all in all the offending cars and resolving the problem.
Sounds more like how GM used to handle QC/design issues than Ford.

 

[jgedde]

Given the slow reaction to remedy the problem and the apparent cluelessness of the dealer network as a whole on this issue, your comment would seem to be accurate.
By itself, that would suggest the cost of a real fix for it is very significant, to the point where Ford would rather fight with individual owners, than get into the drill of bringing all in all the offending cars and resolving the problem.
Sounds more like how GM used to handle QC/design issues than Ford.

Amen to that! I got disgusted with GM service and bought a Ford. No matter what went wrong with my GM, they always seemed to want to make it my fault. It's like they're conditioned that way. Multiple dealers too...

 

[Boosty15]

I sure will.

Any luck on that TSB #?

 

[v8440]

Any luck on that TSB #?

Not yet, but soon. When I picked my car up, the lady told me that the person who could close out a warranty ticket was not there right at the moment. She said that they would mail me the paperwork you normally get at the counter when you pick up your car. I'm assuming that the tsb# will be on that paperwork, and it should be arriving soon.

 

[shahram72]

We all need that TSB number badly! Just to show there is a problem. Had another Mustang owner drive my car yesterday and he confirmed it was there and not on his GT. Mine is a V6.

 

[v8440]

I know you do, and I'll post it just as soon as I get it.

 

[theredmeadow]

Not yet, but soon. When I picked my car up, the lady told me that the person who could close out a warranty ticket was not there right at the moment. She said that they would mail me the paperwork you normally get at the counter when you pick up your car. I'm assuming that the tsb# will be on that paperwork, and it should be arriving soon.

couldn't you just call the service desk and have them open your case and the TSB# will be on there? i'm not trying to be mean at all but in this day and age do we really have to wait on snail mail? :shrug:

 

[Boosty15]

That is most likely the easiest way, but that doesn't mean its the most convenient way for him. You know. With all this adulting we have to do now days. Just be grateful he has a TSB # at all.

 

[v8440]

I called the dealership (not driving there, it's 30 miles away) and asked about it. They JUST called me back. Here it is: SSM45938

 

[Boosty15]

I called the dealership (not driving there, it's 30 miles away) and asked about it. They JUST called me back. Here it is: SSM45938

AWESOME! Now we have something that forces them to aknowledge theres an issue with our cars. :cheers:

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