My truck has been having a vibration issue for a few months now. I have had it almost 8 months and it only has 5500 miles. When I bought it new, I immediately replaced the stock "slicks" with new BFG All-Terrains. Everything was fine, then all of sudden the truck starts to vibrate at speeds above 60 mph. Thought it was the balancing, so had the tires balanced over and over again with no improvement. Took the tires back to Discount, and they replaced all four for free. Actually just went from a 325 BFG to a 305 BFG. Replaced the tires and the vibration is still there. I just noticed yesterday, that when I accelerate the vibration goes away, when I let off the accelerator the vibration is at its worst and when the truck is set a cruise control at 65+ mph, the vibration is off and on. It vibrates for a little while, then stops for a little while.. Hmmmm, I am baffled. Maybe the driveshaft is out of balance, the u-joints are bad, harmonic balancer is bad!!!!! Thanks to all in advance...

CJ

 

what was the stock size and confirm the new size please...maybe a drive line angle issue.

You may have to shim the carrier bearing slightly as a fix.

Any lift on the truck?

 

Stock size was 285/65R18 and the New Size is 305/65R18.. I have a 2" leveling kit, thats about it... I really don't tow or haul much either.

 

just the leveling kit may have changed the driveline angle enough to cause the vibration. If I were you I would try a 1" shim between the carrier bearing and the mount. See if that helps.

 

Is the 4wd drive shaft on a live axle?

 

the front is a live axle, same as the rear.

It is not the front that is causing the problem. It is the rear driveshaft.

 

Thanks alot Senix... First thing tomorrow, will go have it looked at.

 

U need to find out what kind of vibration it is first. Make it vibrate and then throw into nuetral see if the vibration is still there. If its then its speed related vibration: wheels and tires, axles, bearings. If it goes away in nuetral then its possibly a torque related vibration: differential, driveshaft, etc... But i have seen driveshafts cause a vehicle speed related vibration it is rare but possible. I am actually working on a f 150 with a vehicle speed related vibration and the driveshaft is out of balance. Quick way to see if your driveshaft is out of balance is to mark the driveshaft. take it loose and rotate it 90 or 180 degrees. the vibration should change whether it worsens or lessens if it is the driveshaft.

If it is speed related then its probably in your wheels and tires. If so take it to a Ford dealer and tell them to balance the tires using Road Force and Matchmaker technologies, they will know what u r talkin bout. Most tire shops do not have these capabilities but some do...

If its an engine related vibration then it should vibrate with the truck sitting still. U would just have to rev it up until u hit the rpm's that it vibrates at when u r driving down the road.

If its a high frequency vibration: real fast feeling, possibly driveshaft, diff's, possibly pinion angle.

If its a low frequency: slow feeling vibration, more than likely wheels and tires or wheel bearings...
Where do u feel the vibration? Seats, floor board, steering wheel?

 

Wow great info.. Ok first off I have had the tires and wheels replaced twice, balanced at least 5 times, 2 of those times they were "Road Forced". They just built a brand new Discount Tire up the road from me, and they have a "laser" balancer now, even tried it. But no matter what type of balancing was done, it still is vibrating. So it's safe to say, its not tire or wheel related.

The truck does not vibrate below 60 mph. At speeds higher than 60, I feel vibration throughout the whole truck, but I feel and see it in the seats and center console. The speaker on the front passenger door rattles too. Its not too bad, but its bad enough to annoy the crap out of me. To the point of getting rid of the truck. I can make the vibration really noticeable if I accelerate quickly from 65 to 75 then immediatley let off the throttle. That is when it vibrates the worst. Oh and it does it loaded or unloaded...

I really do appreciate the help...

 

Laser balancer SWEEET!!!
No prob on the info man, beins it vibrates the worst when u let out of the throttle sounds like it may not be in the driveshaft, but it is possible. Id try rotating it like i talked about. When dealing with Noise and Vibrations its pretty much a process of elimination, know what i mean? I would def. start with rotating the driveshaft and go from there...

 

Will do, I have a feeling its either the driveshaft or like Senix stated the putting a 1" shim between the Carrier bearing and the mount. It seems that the 2 piece driveshaft used on the SD's are more of a problem then anything. Wonder why Ford just didnt use a one piece driveshaft.

 

I did a leveling kit on my 06 f250. result was a vibration around 40-50 mph. Fix was a shim for the carrier bearing. So personnally since that has been done to this truck...and the tires have already been looked at more than once I am inclined to invest 15 mins and shim it and drive it.

 

Well if its thats easy, I will just do it myself. Problem is, I really have no idea what to do. Unless there is a website I can go to with pictures...

 

It is easy, crawl under the truck, on the rear driveshaft you will see the carrier bearing, two bolts, don't recall the size but somewhere around 3/4" socket size I seem to recall.

Remove the bolts, put a shim in there and re-install the bolts.

If you got the leveling kit from a 4x4 shop, go back to them and kindly ask them for a shim. It will have the holes already. Heck they may do it for you if you had them do the leveling kit in the first place.

Not saying this is your issue, but I would start there myself.

 

Did the vibrating start right after u installed the leveling kit?