03 driveshaft problem

[SNAKESWINGER]

Picked up my 03 Cobra last week and it has the bad vibration between 72 and 95mph which is worse at around 80. Seems to be synchronous with driveshaft rotation, definately not tires or clutch. So I jacked it up and climbed under to see what was up.
Put my dial indicator on the tube1" up on the tube from the yoke at the trans end and then on the rear end. Total indicated runout is .55mm (+.03/-.03mm) Then measured the tube for roundness in 6 places and it measures 90.07mm (+.04/-.04mm). Conclusion: Driveshaft tube is round but is welded to yokes off axis or centerline. Would be interested to know if anyone without the vibration problem could take some measurements and verify their driveshaft runout.

I worked building truck driveshafts for 2 years and we had to hold under .10mm T.I.R. or redo the shaft

 

[Mowgli]

I can tell you from my TWO previous bad 03 driveshafts that that runout is WAY over spec. That was worse than my first driveshaft, and THAT one vibrated my car at 65mph!

Take it in. Tell the dealer your problem, and your measurements. Tell them to call the SVT line right there. Don't drop off your car, unless they insist (sometimes you can't get the new driveshaft ordered until the dealer goes thru diagnostics themselves, which I'm sure they'll want to do).

Anyhow - SVT will also tell them to order a new driveshaft.
When it comes in, take your car in, they'll install it and 1/2 day later - no vibe.

Good luck with it. I can tell you as a "post viber" that the car is a dream.

 

[Black2003Cobra]

Mowgli - any chance you can tell me what the color stripes are on your new DS!? Also, do you or did you ever notice any vibration under acceleration, (only), as opposed to "at speed".

 

[Mowgli]

Sorry - haven't been under car since 1st DS

I was only under the car when the original driveshaft was on it. Since the first DS replacement and then this new "redesigned" DS, I haven't been under it.

I expect if you get a replacement DS ordered now, it will be almost 100% certainly be one of the "new" DS's. I can't imagine them getting anyone one of the old DS's to fix a vibe problem now. Not with all the attention this problem got at Ford.

That being said, my first replacement DS didn't solve the problem, but I was one of the first to have the problem and go in for it. That one was put on the 2nd week of July.

The "new" DS I got last week.

I do still notice a feeling of power during acceleration, maybe a "rumble"? But I feel the same thing in my friend's 2000 SS and my uncle's 2001 Z06.

And actually I never felt that before because the "vibe" masked it. Thats how bad it was, or how slight the "acceleration rumble" is. Actually the more I think about it, what I feel now is jus the engine making power, and not drivetrain related. Because I fundamentally "Sense" it coming from up front, and don't "feel" it at all in my seat or the chassis like with the "vibe".

Sorry for all the words in quotes, but thats the best way I can describe it.

Hope this helps.

 

[Evilcartman]

SVT told me last week that they pulled all the "bad" DS's and have a new one released to all the parts depo's. They are fully aware of the problem and I have one on order. No big deal, it's just out of balance.

 

[Black2003Cobra]

Mowgli - that's OK. At least you replied! My order for the new DS was placed after they said they were issuing the new ones, so I was certain I wouldn't get an older unit. Actually, they told my dealer's parts dept and the tech that it was definitely going to be one of the new ones. The problem is, they also told my tech that the new DS would have different color stripes than the old ones, but that's not what I see. My new one has black-white-black stripes - same as the old one. (Unless I'm not remembering what the original one was!)

I wish I could drive another car to compare the vibration I feel during acceleration to see if it's the same, but there aren't any around. From what you said, sounds like this may be normal. My tech didn't make any comments about it so apparently he didn't seem to feel there was an issue. (He noticed the official "vibe" right away w/o my even having to point it out.)

Anyways, again, thanks for the reply.