2001 Ford Supercrew ... cant find whats causing vibration...

2001 Ford Supercrewhas the KP 6link under it, 265/35/22 rubber. balljoint flip up front, etc It has a nasty vibration above 60mph when DECELERATING. You can feel it in the seat of your pants.Got the driveshaft balanced, made sure pinion angle was right, and got wheels balancedStill shakes horribly....  anyone got any ideas?

Edited: 5/19/2009 8:12:14 PM by Layumon22s

bad brakes?

brakes are fine, i looked at them when i had the wheels off getting them balanced It's not when im hitting the brakes ... just when i let off the gas pedal

Carrier Bearing??? 

How long does it vibrate after you let off the gas? Is it constant till you accelerate again or does it fade out after a few seconds?

it still can be your brakes may b not the pads but warped rottors may want to take the wheels off again and have the rotors spun. just did some brakes on an astro that  was shaking like you say and it was the rotors.  hope this helps

I was thinking a possible driveshaft issue. In the angle or might be bent or off balance. Or what caddyclipped said carrier bearing????

has a 1 piece drive shaft  It vibrates untill you get under 60mph again. you can feel it a tad at 55 but under that its fine... just at 60 it kicks in vibrating bad

im thinkin its a pinion issue when the pinion kicks up during decelartion.

Edited: 5/19/2009 11:20:24 PM by JayMac

I know this is going to sound crazy but my 01 Supercrew did the same thing, and I thought it was torque converter shudder. But it ended up being a #3 cylinder miss fire, the famous spark plug problem the 5.4's have where the plug strips out. It wasnt a violent vibration, but bad enough I could feel it. If its extremely bad I would guess driveline like mentioned above