I posted this here not knowing for sure what is causing the problem. I recently purchased a 1995 Ford F150 XL supercab with a 5.0L engine and auto trans. Problem is that I get a vibration between 30 and 45 MPH. It's not just a steering wheel vibration, the whole truck vibrates. After 45 MPH the problem seems to still be there, but to a lesser degree. I checked all three u-joints and the front end seems tight. I just had the front tires balanced and the front end aligned. I just changed the dist. cap and rotor and the spark plugs were changed 7,000 miles ago. No vibration while in park and reving the engine. Any help is appreciated, I'm at a loss?? Possibly a bad motor and/or trans mount?
Thanks for your help.

 

double check the u-joints, they may not look bad but make sure that they are not frozen. (have to pull the driveshaft)

 

is this a under load. or at light criuse. if under load. make sure #7 and #8 spark plug wire's are not routed next to each other. they are common to jump spark due to the firrng order ending in 7 and 8. there is a tsb from ford. not sure if this is your prob. can you feel the vib in the seat of you pants or in the steering wheel or dash.

 

The problem occurs under both light and heavy acceleration. The vibration seems to be through the whole truck, not just one specific area. I did notice last night though that when I let off of the gas the problem diminishes and sometimes goes away, but as soon as I step on the gas again it's right back.
Thanks!

 

with your truck in park can you move your drivesahft at all by hand? if so, replace U joints

Next, has it ever been lowered, lifted, or carried an excessive load?
if so maybe the pinion angle is wrong, you can buy a cheap little gauge at any parts store ($5) and put it on the driveline right in front of rear axle if its in the negatives (between -2 and -7) then that is ok

then, rear tires unbalanced will do a lot of vibration
and maybe the driveshaft is off balance


lots of things to check with driveline vibrations, and most of it is going to be trial and error till you hit it

L8r,
Navi
www.OverDoseCustoms.com

 

If it subsides when you let off the gas then its something to do with drivetrain, not tire related. If the truck is stock then I'd put my money on driveshaft ujoints.