This truck is driving me nuts! Love the truck hate all the little things going wrong. Got a 05 fx4 5.4 with a shake wright at 50mph or 80kms for us canucks and vibrations when hard breaking at high speed. Is this related? I did the tires rotated and balanced still there. Also at 90 000 k got to change the rear pinion seal already.

 

Had the same problem on my 04 Lariat screw. Replaced my front rotors and pads problem went away. I would have rotors checked for warping.

 

Well first if youve been hitting alot of mud and just ran er through the car wash that wont do. Try getting under the truck with a pressure wash and clean off the back of the wheels. Could be dirt giving you that vibration. And if it still shakes take the rotors off and check them and possibly machine them.

 

I had the same vibration on my 04 screw. Changing the rotors got rid of the problem.

 

Thanks guys great info will try that and post later.

 

my problem with my 97 was the idler arm had loosened itself off. tightened that back up, reset my toe and its quite a bit better.

 

I've had the same problem for some time now. I had 24's on my truck and could never get it to go away... I signed up on this forum for this reason... I got two wheels replaced, got them balanced from every shop with-in 50 miles of my house and nothing... So I just sold them.... Now with the stock set I can fell it alittle.... I thought it might have been the rotors but didn't want to spend the money but with what the other guys said I'm tring it now.

 

..X2

 

Pardon my ignorance fellas, but what do the rotors have to do with driving down the road with no brakes applied? I've got an '04 SC 150 (4.6L) that I've had vibration issues with since day one. I've had the tires replaced time and again, road force balanced, the counter-balance placed on the drive shaft, the drive shaft itself replaced, the ring and pinion replaced and the dampening system put on the truck. None of it did a thing for me. I've had two guys recently tell me that my problem is a design issue in the two-piece drive shaft and its offset. Both suggest that the harmonic imbalance at certain speeds, in my case, also approx 50 mph. Both state that the problem can be fixed by buying an aftermarket driveshaft, one piece. I've had it with the problem and am willing to try it, provided it's valid and worth the investment. Any insight from anyone out there regarding this issue is appreciated.

 

look at your tire wear carefully.
my vibration at 50mph has severly diminished after i noticed cupping and aligned the front end a little better than it was. i had cupping on the inside of the right front and the left appeared to be getting wore down faster but evenly. my 2 cents would be to insist on watching billy joe in the shop do the alignment.

 

Yes, check your tires for uneven wear, out-of-round and broken belts. Check your U-joints.