Got a weird vibration around 65 and up on my Excursion. New ball joints, shocks, tires(Had them balanced 3 times but still haven't ruled them out) Had driveshaft checked by a really good local driveshaft shop, rear end oil changed and shows no signs of any problems. Also new front rotors.

Worse when the camper is on there, dude at the tire shop said everything looks good and blamed it on the driveshaft which I told him already checked out.

What else? Tires are almost a year old but still look new, don't wanna ink up on new ones doubt tire shop would help.

 

Did they take the drive shaft off and check balance. Some fords have that big donut around it for balance. That or a treat breaking loose on the radials.
Chet

 

Straight driveshaft no center bearing, trust me it's not the driveshaft.

 

I am sure they checked the u-joints?

 

Yes they are new.

 

I don't want to jump the gun, but if everything else is good, might be the Tranny?

 

I don't think so, I Can kick it neutral and with no load on it doesn't change. Also I can rev it up in neutral and nothing else changes.

 

Rotate the tires and see if the vibration changes at all. If it does, I'd blame the tires. Had it happen to me once on my wife's Expedition. I hunted a vibration on that truck for weeks. I was working with a reputable tire shop, so as soon as I told them the vibration changed after they rotated the tires, they replaced the suspect one. The "bad" tire showed no issues - balanced well, no funny wear, etc.

 

Jmatthews,
This isn't a solution but I'm having a similar problem, Take a read at my post and see if it sounds familiar to what your experiencing.
https://www.ford-trucks.com/forums/1...odd-shake.html

 

If it's not the tires you may want to look into the drive angle of the pinion

 

The tire could be oval, yet in still balance. Some tire shops can do road-force testing, where they check roundness that way. Try putting the spare tire on and driving it.

If the output bearing of your transmission (or xfer case, if 4WD) is loose/worn, that could be doing it. Grab the driveshaft where it connects and push it up/down to check for play. Put the truck in neutral first, apply the parking brake, and chock the wheels so that there is no turning force on the driveline when you do this test.

 

My 99 F350 will Vibrate at 70 if my front tires are not to factory specs. (70Psi)

 

ding ding ding ding

 

It's not lifted and the driveshaft shop guy checked it out. I guess I'll try the road force balance there are a few paces that do that nearby.

 

I was just throwing the driveline angle out there J, I know that these trucks are getting a few years on them & the springs are not what they once were & the torque that is thrown at the diff sure twist the **** out of the rear.

Good luck with it bud