Dark_Horse

when i am driving, at about 70-80mph there is a wierd vibration. the passenger seat shakes and i can hear it and see it its pritty bad, the stereing wheel and you can just feel the car shake. i think it cold be the drive shaft, but im not sure. what could cause this, dose any one elss have this problem, any input would help.

sprostang

Sounds like the u joints are bad.

xx9gt6xx

Usually when a tire is loose or balanced incorrectly it could do that. It could also be your u-joints too. But if it does happen to be your driveshaft, get a FRPP Aluminum as a replacement. It takes extra HP from your motor and throws it to the ground with it's lightweight design and is balanced like unreal. Get it checked out...

-Bryan

dlazrael

Wouldn't a driveshaft problem occur at certain rpm's not speeds? Regardless, I had a similar problem with my 95 GT it turned to be a broken tie rod. About a $200 replacement (with labor). Check that out too

2000GT4.6

When I had a bent yoke on the driveshaft (after the TKO500 install I got screwed by my shop) the car would vibrate all the way thru the speedo. It would gradually get worse and worse the faster you went, but it was always present.

It sounds like to me he has a tire out of balance. Usually a tire out of balance will do what you are discribing, aka only have a problem at a certian speed.

BTW, the RPM doesn't have much to do with the driveshaft. It will go faster and faster thru the gears, aka it spins faster and faster the higher MPH you go, the RPM doesn't make a difference.

blackbetty01

Sounds like a tire issue, if it only lasts for a certain speed range. My Mustang will start to shake right before it is time to get the tires rotated and balanced, but not nearly as bad as you are describing. Also I rotate and balance every 6000 miles.

bumpinwheels95

i actually had that happen to me n it turns out that two of my cynilders were missfiring... is your check engine light on>?

04GTMustangRob

I always had the rule of thumb about tire balance. if you can feel a shake in the steering wheel, your front tires are out of balance. if you feel it in your seat, one of the rear wheels is out.

Tim37

Have you ever used fix-a-flat if so go have that crap taken out. that will througth a tire so out of balance that it will cause that problem but for the most part you wont feel a tire balace problem in your seat unless it is extremely unbalanced.

00StangFF

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