aguy told me prob is exhaust suport . just remove gold coloured suport from the tranny . good luck!

 

Know of anybody that can lend you their tires and rims, to try to see if this is the problem???

This way you would know for sure if it is the wheel/tires or the truck driveline...

 

envrmtly
What rims are on your truck ?
17" Chrome steel ?

Did the dealer offer to swap tires / rims for a simple road trip ?

I would strongly agree with others here that a wheel / rim problem might be associated with this behavior.

What is the rpm / speed when it occurs ?
Does it build as rpm increases ?
Or it more indicated/pronounced at a certain speed say 45 mph ?

How about a driveshaft balance check ?

 

Thank you for the information about the hunter balance system. I purchased Cooper tires for my 2001 Screw {4x2} about 8,000 miles ago. I noticed a vibration from day one, I assumed it was due the increased tire size and the fact I upgraded to a LT tire. The vibration was not that bad, I had the tires rotated and rebalanced at BellTire and noticed a side to side vibration in the seat and center console. After taking it back to the tire store 3 days in a row they sent me to the ford dealer. The ford dealer pointer to the tires and sent me on my way. {little help}
So I took it back to bell tire and they said I should place a passenger tire back on truck to get the smooth ride. So I turn to the F150Online forums to get some information.

I found out about the Hunters GSP9700 system and located one at Discount Tire. $80 latter I'm on the road no vibration and I am once again a happy camper with my Cooper Tires.

Berlinger
5.4L {4x2} Screw
Edelbrock IAS shocks
Road Master Springs on Rear
Discover A/T Cooper 17 inch LT tires 275/70/r17
Tow 30' Travel Trailer 5800lb
Hensley HItch

 

I HAVE HAD ISSUES WITH THE '01 SO MUCH, THAT I TRADED FOR AN '02. WORLD OF DIFFERENCE !!

AND I THINK FORD JUST WENT BACK TO 0% INTEREST HERE IN FLORIDA AGAIN.