Help 04 vibration

[98cobra]

I have been a mustang owner for years and I purchased a 2004 cobra convertable with 6400 miles on it in May. While bringing it home from new york we had a bad vibration at 60 and up. owner said probably flat spot and he would pay for tires. Once home we discovered possible previous damage to the front end. lamatta performance here in Orlando has exausted efforts to find it??? We have checked frame it is straight put new springs,shocks,front control arms, new cat back,strut tower brace,full length sub frame connectors, alinment, new tires balance,changed wheels from one that was ok,rebalanced drivshaft, checked pinon angle ok and swaped out the intire IRS from a donan car and no change??? The car drives straight as an arrow and has very slight vib at 58 to 60 and at 62 to 68 shacks you brains out and then settles out at 70 to mild vib until 80 and then is not to noticable. Please if you have any ideas let me know. thanks for your help Cobra98

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[Dragon03]

Have you tried reaching those speeds using different gears......ie try it in 3rd gear and then try 4th?? Something may be going on in the tranny maybe Good luck:biggthump

 

[batman]

tires..driveshaft..bearings

 

[sonic02gt]

sounds like input shaft

 

[98cobra]

Yes different gear makes no difference. Does the same at 2krpm or 4krpm. I have kind of said do to that fact?? It is in front end or from drivshaft back? Thanks for the help.

 

[Mr. Unknown]

there is a metal chunk underneath the differential. Do you have that?

 

[killer03]

If you feel the vib. in the steering wheel then you should be looking front tires, bearing, suspension...... Seat of your pants then start with the drive line, rear suspension, tires...... I know input shafts can cause this type of problem.

 

[98cobra]

I don't thing IRS has that do they? I will look.

 

[98cobra]

Yes the wheel does not shake back and forth but the car shake/vibration can be felt though every thing as it is really severe. I am thinking of renting small veido equipment and shooting all four wheels while driving and then rear??? I am getting despreat.

 

[Mr. Unknown]

I don't thing IRS has that do they? I will look.

yes it should. Just infront of the differential.

 

[Fordman]

After i bought my car i noticed the same thing, almost to the point of making me have a migraine every time i went on the high way, it also whined a little bit too.
I took it to ford (under warranty) they rebuilt the rear end and it was still there.
They found out it was the drive shaft. The u bolts had wallowed themselves a bigger hole and vibrated after 60 mph. they replaced the drive shaft and all is well.

 

[98cobra]

We replaced both drive shafts but not sure about the bolts? tHANKS FOR THE IDEA

 

[98cobra]

04 vibration

Whay U bolts?? There is no u Bolts on a 03 04 drivshaft they had the ujoint attached to the flange that bolts to the pinon? Was it the universal joint u bolts? thanks

 

[98cobra]

I just looked at mine it has no u bolts on the driveshaft the universal joints are pressed in?

 

[98cobra]

Yes metal chunck which is the cross support is the support is there.

 

[Fordman]

Not sure , this is what the service manager told me that the bolts on the shaft had wallowed themselves a bigger hole near the rear end. I never looked, just took them for there word. cause whatever they did it fixed it. maybe the service manager messed up the explanation from the service tech.
I will see what the explanation says on the papers they gave me and let you know


EDIT: checked invoice and all it said was replace drive shaft assembly. sorry no help there.
I guess if you run out of options as a last ditch thing you could see about the following
Have any friends with and 03/04? might be possible to borrow the drive shaft (no small task though) to see if it cures it. they are expensive to replace.

 

[98cobra]

Yes thanks for the help everyone great Cobra site to be part of now. John