Vibration between 50 & 70 mph

[shahram72]

So why after mine is fixed, did it come back? This is so puzzling!

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[zanGTA]

This is a million dollar question. IMHO once we have this answer we all will be able to solve this problem. Mine too was perfect up to 6k miles and then started. I moved the irs and it got worst.

I suspect that is a irs moving problem. You do a burnout, go to drag strip and as there are only 4 screws in too big holes that holds the irs the irs moves, the angles changes and all system get unbalanced. The vibrations with time destroy your differential and so on.

My personal supposition eh, I'm a software engineer, not mechanical.

 

[Juben]

This is a million dollar question. IMHO once we have this answer we all will be able to solve this problem. Mine too was perfect up to 6k miles and then started. I moved the irs and it got worst.

I suspect that is a irs moving problem. You do a burnout, go to drag strip and as there are only 4 screws in too big holes that holds the irs the irs moves, the angles changes and all system get unbalanced. The vibrations with time destroy your differential and so on.

My personal supposition eh, I'm a software engineer, not mechanical.

If your theory proves correct, then we should be able to remedy the problem with Steeda's $40 subframe alignment bushing kit. I placed an order for them today, so I'll see if it makes any difference with my car.

 

[zanGTA]

If your theory proves correct, then we should be able to remedy the problem with Steeda's $40 subframe alignment bushing kit. I placed an order for them today, so I'll see if it makes any difference with my car.

I did that and was worst. Why?

A friend told me that those holes are so big for a specific reason. The rearend is aligned from beginning in a way to get everything balanced and each car is a bit different. By this theory, you could have a perfect balanced car with the screws not perfectly in the hole center.

Maybe that again is my situation.

Why a car developes this issue? Why some cars that was fixed get the problem back?

If my iphotesis is true, you have to balance everything after steeda's kit if you are so unlucky like me. And maybe after that, the irs will not be able to move and the problem will not come back.


Boh...

 

[offroadkarter]

I feel like I should chime in again and say that I do have a vibration again after the new DS. Its a bit different from before and not quite as bad, but none the less "a" vibration is back. My car is still 100% stock so this isn't from some suspension modification or something.




My car is staying parked til spring right now so hopefully someone finds a solution. I see people taking about realigning the entire subframe and I know Kelly @ BMR was talking about driveline angles. Who else wants to experiment and go down one of these routes to see if this solves the issue that Ford will most likely never fix until the S650 comes out?

 

[theredmeadow]

I feel like I should chime in again and say that I do have a vibration again after the new DS. Its a bit different from before and not quite as bad, but none the less "a" vibration is back. My car is still 100% stock so this isn't from some suspension modification or something.




My car is staying parked til spring right now so hopefully someone finds a solution. I see people taking about realigning the entire subframe and I know Kelly @ BMR was talking about driveline angles. Who else wants to experiment and go down one of these routes to see if this solves the issue that Ford will most likely never fix until the S650 comes out?

must be nice to have the means to park such an expensive car for 5 months...

 

[offroadkarter]

must be nice to have the means to park such an expensive car for 5 months...

Did you just assume my financial means????

 

[theredmeadow]

Did you just assume my financial means????

lol sorry but as much as this car costs i'm not parking it for 5 months out of the year! :eyebulge:

 

[shahram72]

And I have never done a burnout or so much as a hard launch on this car and it still has the problem. My 1976 Datsun 280Z, 1991 Corvette, 1998 Lincoln Mark VIII never had this problem. All front engine rear drive with IRS.

 

[speedfrk]

And I have never done a burnout or so much as a hard launch on this car and it still has the problem. My 1976 Datsun 280Z, 1991 Corvette, 1998 Lincoln Mark VIII never had this problem. All front engine rear drive with IRS.

Do it... my car always seems smoother after I nail it on an on ramp. Maybe it moves the cradle a little bit, but worth a try. Plus it's fun!

 

[Von Bek]

Mine just started with the vibration after my first set of new tires for the rear. Had them rotated and rebalanced and didn't fix it. Didn't even know there might be an issue with the driveshaft. What do you recommend to tell the service guy so they know what to look for when I bring it in. I think it's just past 9k miles so everything should be on them.

 

[shahram72]

Mine just started with the vibration after my first set of new tires for the rear. Had them rotated and rebalanced and didn't fix it. Didn't even know there might be an issue with the driveshaft. What do you recommend to tell the service guy so they know what to look for when I bring it in. I think it's just past 9k miles so everything should be on them.

And this is why I don't just trade it in for a GT. No guarantees. Nothing we can tell you, just tell them u think it's driveline vibes and please check alignment of the rear end, it's not just balance issues.

And as a reply to the other post, maybe I should try a hard launch. Maybe in reverse! Shit, it's already broken! Maybe I'm too easy on her! I bought the V6 for a reason... I'm not a speed junkie, it's plenty for me. I'm happy to cruise.... And I like my dash with the black fake CF better than the other models. Honestly I think the GT should have had the black CF. Looks racier to me.

 

[BlackGT]

Well, the dealership had an engineer take a look at my car today and he agreed that there was a vibration but wanted to do some research before making a decision for the next repair.

 

[Sick03L]

After fixing mine myself... 2x and having it come back somewhat. I'm 99% sure its in the alignment of the rear end and cradle geometry being off. The DS balance is only part of the problem.
I'm going to align the cradle, diff bush inserts and shim the cradle as needed to get everything aligned true.
The first time it started vibrating was after the very first launch from a stop. Something shifted.... all makes sense now. It would come and go. I think we're making progress with this issue and I'm close to solving it for good.

 

[Mr981]

Well, the dealership had an engineer take a look at my car today and he agreed that there was a vibration but wanted to do some research before making a decision for the next repair.

After nearly two years of this thread, and numerous people posting have lemon-lawed their cars, don't you think Ford has a pretty good idea of what is going on? Two years is an awfully long time to have an obvious problem with the car that is still being built just like the early models
My first thought being that the requirements to fix the car--bring the car in, eliminate the tires and DS as the offending components and then get into the nity-grity of shoring up the differential cradle's alignment with the DS, has to consume a lot of time and warranty dollars, so Ford is slow walking this fix, hoping a number of people with the problem will just give up and live with it.
I would hope that Ford would take a very proactive approach and issue a TSB for all S550 cars built so far but that doesn;t seem to be happening.

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