So a few weeks ago I got 4 new tires on my 2008 F350 cc 4x4, 51k miles. Took it on a trip towing my 5th wheel camper, and I noticed it felt weird driving. I sensed a vibration. I drove it for over a week trying to narrow down when I felt the vibration. I took the truck back and had the tires checked for proper balancing and alignment. All ok there. But when I am on the highway or driving down a road around 50mph, I feel a vibration. Not in the steering wheel, but more through the cab. The truck seems fine when driving through town. Doesn't sound any different, and doesn't feel any different at idle. I want to get it in to the dealer to have it checked, bUT just looking for your thoughts.

 

I suspect tires/balancing. Try a different road if possible, and validate if your tire pressure is different or not. Sometimes, tire places max the pressure which will make them feel different. Sometimes, the tires were "almost" balanced.

 

I had the balancing and alignment checked Saturday. One tire was out of balance. But I still get the same vibration. I have experienced this on multiple roadways. But I was thinking before that it was a tire/front suspension issue, but now I wonder if it could be engine related. But I feel like if it was engine related, it would do it all the time.

 

Are your new tires off road tires and possibly more aggressive than your original tires?, After the tires are erased from the vibration list it's time to look at the driveline, "U" joints, carrier bearing, Ect.

 

I had goodyear Duratracs before, and replaced them with grabber AT2'S. I was considering putting the rear axle on jack stands and putting it in drive, getting it up to speed. Not sure if that will do any harm.

 

You changed your tires and now have a vibration/growl kinda problem. Problem wasn't there before. Its not a stretch to think your new tires are to blame. If you doubt, then take your truck up to 50mph and take your foot off the pedal. Still growl at you? Go back to the shop. They can move wheels+tires around to isolate a problem if its just 1 tire.

When I have a problem I always ask myself ... what was I messing with

 

So I jacked up the rear tires off the ground and got the truck up to 65 miles an hour without noticing the vibration. That leads me to believe it's not engine related. Did notice that one rear tire has a slight wobble. I'm bringing my truck to the dealership now to have a coolant leak fixed and I'm going to have them look at this vibration. I already brought it back to the tire shop once.

 

Im pretty sure it may be one of your U-Joints in the drive shaft.....likely the most rear one. You will have to take the driveshaft loose on one end to be able to tell.
Had this same thing happened to me. check it out.

 

Brought the truck to the dealer. The fixed my leaking upper radiator hose, and checked for the vibration. They rebalanced all 4 tires, and put them on the road Force balancing machine. I didn't really get to test out the truck at speed for extended periods of time. So hard to say if problem is fixed. But I should know more over the next few days.

 

Wouldn't I have felt a bad u-joint when I had the rear tires off the ground spinning?

 

Not Really. Perhaps not able to tell that way.
When my rear U-Joint went bad (twice in 200,000 miles)...both times I could in no way detect it was bad by just looking at it or by seeing if it would wiggle with a crowbar. Seemed to be OK.
After disconnecting the rear U-Joint closest to the rear differential it was easy to tell it was bad because part of the U-joint did not move freely by hand at all. Could barely even move it with a pair of pliars.
Then after completely removing the u-joint, it was easy to see it was frozen as the needle bearings in one of the 4 sockets was almost reduced to a fine steel dust and of course bone dry of any grease.
Replaced it and it was smooth to drive again.


Could never feel that vibration at slower speeds or higher speeds but only around 55-65 mph.


The second time this happened to me I knew what it was and wasted no time to replace that U-joint and fix the vibration problem again.
Does not take much time or effort to undo the driveshaft to properly check a U-joint.
Good luck and let us know what you find.

 

Dumb question, but would it only be the main drive shaft u-joints. What about the front axle u-joints? What would I feel if those were bad? I still noticed the vibration today.

 

If your front axle u-joints are spinning while driving then its a possibility. But I would assume you don't drive in 4x4 at that speed and also that your front hubs are not manually locked.
Should not be turning if not locked.
I'm still confident that until you removed that rear driveshaft and checked those U-joints by hand for binding then you cannot rule out that they are not the source of your vibration.
Good luck

 

Thanks, you are correct-in haven't used 4wd in a while. I just wasn't sure how the front axle u-joints factored in (if at all). I will definitely be checking out the driveshaft ujoints when I get a chance this weekend. Everything you said makes sense. Would the drive shaft from transfer case to front axle be part of this equation? Even though the truck only has 51k miles, it is 9 years old. What brand u-joint do you recommend? Ford, splicer/GMB, moog?

 

So here is what I know so far. I was driving the truck today, and when I noticed the vibration I put the transmission into neutral. Vibration stopped. I also noticed that the vibration occured while under torque (stepping on the accelerator). This to me leans more towards the u-joints as stated by "4x4". I haven't had a chance yet to drop the shaft, but I did jack it up and spun the driveshaft. There doesn't seem to be any play, but I did notice that on 2 points of the rear ujoint there was greasy spots. I noticed the same on the front ujoint as well. Here is a picture of the rear U-Joint. Is this a sign of bad u-joint?

Rear U-Joint greasy spots?