My 06 f250 has 40,000 miles nad I am getting a bad vibration and humming coming from right under my left foot, Tires just balanced, alignment done, and driveshafts checked. I am at a loss. Vibration and humming start at about 40moh and gets worse up through 70mph and them levels off a little. any suggestions?

 

this may sound completely retarded and probably is but i know that if i have the radio up loud i can feel it under my feet. tripped me out at first until i figured it out. but that probably isn't it since it doesn't describe the hum.

 

did you pull out the drive shafts at some time? maybe they are out of sync.

Check the tranny mounts, maybe one went bad or they are loose

 

A friend had the same problem and his turned out to be the left front wheel bearing, not a cheap fix if out of warranty, but since you have an 06 I'm sure the warranty will cover it as long as you purchased the extended warranty.

 

Do you have any suspension mods?

These may or may not help since you feel it under your left foot ..............

Vibration/Hop at 40-48 MPH, Trucks with Trailer Hitch:
Some 2005-07 F-Super Duty trucks with long wheel base (over 156") may exhibit what is described as a hop on smooth or coarse road surfaces. Although Ford considers this to be characteristic of trucks with a GVW of over 8500 pounds, some drivers may be more sensitive to the condition. There is a damper kit (P/N 5C3Z-5D008-A) available to correct the hop under the described conditions. It will not correct shimmy, harsh ride or vibration after hitting bumps. TSB #07-5-11.

Old post I kept:
There is a TSB concerning driveline shudder. The carrier bearing is re-shimmed, using 1/4 inch thick shims. I would pull the driveline, and inspect the u-joints carefully, and the carrier bearing for roughness, and the condition of the rubber mounting for the bearing. this is kind of off the wall, but can be a factor, has the transfercase fluid been changed recently? If it is overfilled, it can cause a vibration, ask me how I know. I would inspect the driveline components very carefully, driveline angle, and the driveline balance. A good driveline shop can balance both shafts, definitely do this if u-joints or carrier bearing is replaced.

TSB
99-07 Super Duty F-Series Two-Piece Driveshaft Shudder:
Some trucks may exhibit a vibration on moderate to heavy acceleration from a stop. This is usually due to too high of an angle through the center u-joint. The correct angle through the u-joint should be 0.5-3.0 degrees (compare front shaft angle to rear shaft). Check the engineering number of the center bearing bracket to ensure it is the correct application, and replace if necessary. If the bracket is correct, the shudder may be corrected by shimming the bearing down from the bracket using up to three 1/4" shims, part number E0TZ-4A209-A and two grade eight bolts long enough to expose three threads above the nut when tightened to 46 ft/lbs. Loctite is recommended. Broadcast Message 0518, 1475; TSB 04-22-7, 05-17-6, 06-23-4.

 

I had the same problem after I installed a turbo back exhaust. the larger diameter exhuast tubing was vibrating again the transmission cross-member. I hope this helps

 

Thanks for all the info..I will try these out and see if I can get it fixed. It does seem to be worse when I am accelerating...If I stand on the running boards and rock the truck up and down I am getting a real bad squeking from under the front left tire area..right under the floorboard were I am feeling the vibration. Just had rear driveshaft balanced and have a brand new one on the front.

 

I Too Have An 03/f350. That Exact Vibration Happened To Me. It Turned Out I Needed A New Front End. I Was Torqued As The Truck Had 67km's On It And I Had To Fix It At Kal Tire, Cause The Local Ford Shop Was Booked For 10 Days, And I Was On Holidays. They Put In A Moog Front End, Which Is Greaseable, Unlike Ford. Problem Solved. New Front End, 3 Injectors, 1 Broken Tow/haul Button In 108 Km's. I Can't Complain, The Truck Has Been Pretty Good. Knock On Wood. Good Luck.