Vibration above 70 mph - possible driveshaft?

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ChasingStyx

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2007 Limited 4.6L AWD/4WD

At speeds above 70 mph, I'm getting some vibration (resonance / almost a grinding feeling) in the steering wheel. (Don't feel much below that)

My first thought was a tire(s) out of balance, so that will be the first thing I have taken care of. But I also know that the driveshafts in these things are notorious for crapping the bed, and they are not serviceable (can't replace the carrier bearing, etc..)...

Assuming my wheels get balanced and the vibration is still there, is there a somewhat reliable way of determining if the driveshaft is toast? Before spending $700+ on a new driveshaft from one of the various aftermarket driveshaft places, I'd like to know if that's the actual issue.

Thanks much!
 

curtis james

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when i had a drive shaft go out of balance i could feel at slower speeds and it got worse with speed, was able to get balanced at a shop for cheap, sounds like out of round tire or rim maybe threw a weight.. hopefully it is a simple fix for ya.
 
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Just a good rule of thumb from my previous life as a tech. If you feel something in the steering wheel only it’s typically going to be something related to the front end/wheels. If you feel it in the seat of your pants it’s typically going to be found in the rear end/wheels.
Driveshafts will usually shake the whole vehicle. (4wd issues can sometimes mimic a drive shaft) As previously mentioned driveshaft issues usually show at lower speeds and the vibration will increase with speed. If you have a blown out Ujoint or carrier bearing/center support it can be quite a violent shake/bounce at lower speed. In that scenario you will typically experience a clunk sound/feeling when going into gear from park if you have an automatic trans. More difficult to feel if manual trans.
Bad motor mounts/trans mount can also give similar feedback but still much different feel than a bad Ujoint.
Hope this helps speed up diagnosis time for someone.
I don’t post much on this site as the ST is my sons truck but I do lurk from time to time.
 

ChasingStyx

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Just a good rule of thumb from my previous life as a tech. If you feel something in the steering wheel only it’s typically going to be something related to the front end/wheels. If you feel it in the seat of your pants it’s typically going to be found in the rear end/wheels.
Driveshafts will usually shake the whole vehicle. (4wd issues can sometimes mimic a drive shaft) As previously mentioned driveshaft issues usually show at lower speeds and the vibration will increase with speed. If you have a blown out Ujoint or carrier bearing/center support it can be quite a violent shake/bounce at lower speed. In that scenario you will typically experience a clunk sound/feeling when going into gear from park if you have an automatic trans. More difficult to feel if manual trans.
Bad motor mounts/trans mount can also give similar feedback but still much different feel than a bad Ujoint.
Hope this helps speed up diagnosis time for someone.
I don’t post much on this site as the ST is my sons truck but I do lurk from time to time.

Thanks for the insight! I love picking up little tidbits like this where the knowledge comes in handy for a lifetime. Cheers mate!
 

StephenL

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For the record, in case anyone else has a shake another resource, this video is a very useful guide to diagnosis along the same lines as what DAM Sport Trac has written

 

Doug Kaye

1st gen V6 4x2
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If you have a blown out Ujoint or carrier bearing/center support it can be quite a violent shake/bounce at lower speed.

can confirm, in the bad old days drove my 74 Hillman across Zimbabwe to Victoria Falls, ujoint went out somewhere in there. Driving at 50-60mph there was just another vibration/shimmy/shake, nothing unusual then. Once in town and going slow, it sounded like a factory of dwarves down there banging and hammering away..
Local mechanic was able to replace ujoint but the carrier bearing was all torn up. I replaced that with several pieces of radiator hose cut and wedged in place, drove it like that for another 3 years ;-)
 
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