Shaking over 60+ M.P.H.

[Mike Wilson]

Now that I'm back...



All has been O.K. with the Trac except a shake over 60 m.p.h. Doesn't feel like

a tire balance problem. It seems to come from the center of the vehicle, and it shakes

the passenger seat. Steering wheel doesn't really shake or vibrate, and all tires are wearing well since the last rotation and balance. Haven't been off-roading, and haven't hit any

big pot-holes or bumps, etc...



Suggestions?:huh:

 

[Johnny O]

Problem is likely from the rear since the steering wheel is not shaking.

My rule of thimb when I'm not sure what a problem is, is to start with the cheapest alternative first:

Get the rears balanced again, you could have lost a weight.

Check for broken belts. The tread will wobble when it's on the balancer.

Frozen rear brake caliper.

Bent driveshaft.

 

[Mike Wilson]

Tire Balance, O.K....

Tires, O.K., (Rotated front to rear, no difference),

Brakes...O.K....

I'm thinkin' driveshaft balance problem?!?!:unsure:

 

[Woppy V]

I had a vibration that was coming from the center of my trac. Turns out that nut attaching my drive shaft to the transmission and rear diff had somehow become loose. After I tightened em.. good bye vibration.

 

[Mike Wilson]

WoppyV,



I'm gonna check that one first thing in the morning!

Thanks...!

TnB...

 

[Scott Heckler]

I had a bad shock in the back that was causing a shake over 60 for me.

 

[Snooze]

I would have the tires re-balanced.



I had the same exact problem and went nuts trying to find solutions. I had a whole list in order from cheapest to most expensive. I started with re-balancing the tires and telling the crew at Discount Tire to pay very close attention. Luckily they did and my vibration went away. I couldn’t believe it. I was even test driving the truck after the re-balance to the next appointment I had made to look at drive shaft angles. I was able to call them and cancel.

 

[Mike Wilson]

I've had the tires re-balanced, and no fix!



That's kinda what's scarin' me! Might be the drive shaft thing, and I'm 1,800 miles

out of warranty!



Again, I don't do any off-roading that would have broken anything, or thrown anything

out of balance...?:unsure:

 

[Richard L]

I agree as stated above. You probably have an issue with one of the rear tires.



It could be out of balance or you may have a tire worn out of round. It's easy to check with a dial-indicator, and most tire shops and front-endl alignment shops should be able to check that for a small monimal fee.



I had a 1978 Buick regal that had problems with General tires wearing out of round. In fact some tires were so far out of round that you did not even need a dial indicator. You could see it with the naked eye...It was so bad that blind person could see it.



You can probably confirm that it's a rear tire issue by swapping the front and rear tires and the shacking should move from the seat to the steering wheel.



The opter posibility is the drive shaft is out of balance. This was a common problem on some early model Sport Tracs, but it only occurs at the higher speeds above 70MPH. Ford replaced a lot of the original steel driveshafts with new aluminum ones which cured the vibration problem.



...Rich

 

[Gavin Allan]

Worn-out universal joint on the driveshaft.