Hello,

i have a 2005 F-150 STX and for some strange reason when i reach 50 MPH the truck starts shaking but as soon as i hit 51 MPH it stops and thats the only time it does it. What should i do? Is it my Alignment? or should i take it to the dealer its still under warrenty (Extended). Much Appreciated Thanks, its really annoying!!!!

Brian.
2005 F-150 STX
Pioneer Head Unit
With 2 10" Kickers
850 Boss Amp

 

does it have aftermarket wheels? have u done anything to the suspension? new tires? anything u changed?
if u still have oem wheels and tires have u hit a curb lately?

 

no but i did buy the truck from carmax and of course they put on crappy tires, i know some people have told me its the tires but there brand new so i dunno? No curbs i have had the truck for about 3 months now it the shaking was worst but i got my tires balanced but now its at 50 MPH instead of all the time

 

Have the tires road force balanced, not just balanced. it could easily be a tire that is balanced, but out of spec enough to cause vibration.

 

ive been meaning to ask.. wats the diffrence in road force balanced and regular balanced?
my truck does it to at about 55-60mph i need to look into road force balancing. i dont know if my wheels and tires are.

 

i have never heard of road forced

 

With road force balance there is an arm that comes down and will measure the out of round on a tire/wheel combo. With weights, the tire is balanced, but you would still have vibration from the tire at speed.Most Mr Tires have the proper machines for this. Just ask the place whether they can do a road force balance.
The new model F150 due to the stiff frame, it seems that more vibrations get transfered on to the passenger compartment. Also as tires get bigger, they are more likely to have that type of problem.

Do a search in this forum for "road force". You will get lots of hits.

 

My 05 shaked forever when I first bought it. I went through 1 or 2 sets of rear tires before the dealer got a set on there that would take a good balance. I had the same shaking at 55-60mph. They finally was able to get the tires balanced and it took care of the shaking. Now I have after market wheels and tires and they are smooth as could be too. If you do a search there is alot of info. about some of these trucks have the shakes, seems that balancing the tires usually works but sometimes it does not.

 

It could also be your parking brake. There's a TSB on that. I had it it happen. Once I'd reach 80 kmh the entire truck shook. The parking brake wasn't releasing fully.
The dealer took care of it and it hasn't happened since.

 

Well if it's not your tires I would certainly look to your driveshaft. If that driveshaft is not harmonically balanced it will do the same exact thing. Now, from FORD it should be fine, but maybe it has been dinged somehow. I know since I ruined one on my last truck. After I got the new one, it shook at 70mph. I had to have it harmonically balanced and weights added to make it right. Just an FYI if you determint it's not your tires.

 

I had a vibe around 50+ MPH and the dealer replaced my rear end clutch packs and put in a new drive shaft. Also, these trucks are highly sensitive to pinion angle changes.

 

mine shakes at 50+ but its a truck...

 

I have had several issues like this in the past. Once it was the pitman arm, which wasn't seen on the first check underneath, because all the linkage hangs on it when you jack the front up and put it on stands. Found it the second time by levering up with a 2 x 4.

The rest of the times, it was mud/clay stuck in the hollow backs of the wheels. Doesn't take much to throw the whole thing off.

Dave

 

I vote e-brake!

Mine went so far as to lock up the back tires and slide to a halt in the slow lane of I-135. Thanks Ford! Even though I showed them the TSB, they wouldn't take care of it. Even though they installed a "flight data recorder" for a week and it showed "definate bad vibration", they wouldn't take care of it. Even though I told them I had not used the e-brake for 6 months then started doing so again, they still would not even take a look at the e-brake. Even though one of their most seasoned techs went for a ride with me and felt it himself, they still wouldn't look at the e-brake. After I made a 15 minute call to Ford World Headquarters in Michigan at 5:00pm, THEY WERE WORKING OVERTIME THAT NIGHT AND THE PROBLEM WAS FIXED THE NEXT MORNING @ 8:00AM. Amazing what a phone call to the right place will help you get. THANKS LONG_MacARTHUR FORD IN SALINA, KS Only took them a month to get it fixed!

 

My car used to do that, in fact one of my F-150's did too, and both times the problem was a tire was not properly balanced.

Mine didn't start shaking until 60, but shook from 60 - 65, then smoothed out to normal after that.

Suggestion: Anytime you get your tires rotated & balanced, go straight to the highway and take it up to about 70 - 80, just to make sure there's no problem. If it shakes & shimmies, take it right back, and make them keep working on it.