I have a 1996 f150 351 4x4 e40d, shortbed. I've been hearing a sqeaking sound coming from underneath the truck while driving. its not a belt because it dosnt do it while in neutral while reving the motor. today i replaced the u joints and that didnt change a thing. it squeaks around 30 mph.it only squeaks when u have ur foot on the gas, as soon as you let off it stops. its not the breaks, those are new. and the front has new bearrings. im worried now that it is the transfer case.anyone have any ideas that can help.??!!!

 

does the squeak ring at a consistent wavelength to anything? if so, its drivetrain. if it just sounds like random racket, it could be suspension or frame mounts.

 

ya it sounds like drivetrain to me, only makes the sound when im driving, like something rotating. just not sure what it is, the truck still drives fine. im going to change the t-case fluid this weekend

 

Have you checked the U-joints?

 

they are brand new, i replaced them because i thought that was the problem

 

I have the exact same problem with my 2007 ranger. Really interested in whether you solved the issue.

 

turned out to be the stupid heat sheild that goes over the cat, a couple of the bolts rotted and broke so it was slapping around underneath the truck and making noises.