strange grinding sound

[wayfastwhitey]

hi, i just bought an 01 f250 and when you drive it theres a strange grinding noise. it sounds like metal on metal grinding. but the weird part is it only happens at quarter throttle. you can control it with the pedal. when you push on it to speed up you can hear it go by and when you let off you can hear it go back by almost like something on the end of the pedal is rubbing something but it only does it while its moving. if you put it in neutral and coast and hold your foot at quarter throttle itll make the noise too. it does it in every gear. the faster you are going the loader it is. anyone have any kind of idead of what it could be? ive looked for obvious signs of rubbing and ive checked the wheel bearings and all that,

[wayfastwhitey]

no ideas anyone?

[Fred Swanson]

Have you checked the carrier bearing on the rear driveshaft?.....Fred

[Galaxie]

Can you post a video? There are so many freaky things it could be. Heck it could be a bad U-joint you can only hear or feel at a certain RPM or speed.

[wayfastwhitey]

i never checked the carrier bearing, ill look at that, and i dont think youd be able to hear it in a video i can try and take one but i doubt it would be loud enough to hear, and i know theres a bad u joint in the drive shaft but i have doubts that it would be that

[BryanH]

I would start with the u joints. They need replaced anyway and it takes 10 mins. My center went out and it was simuplar to this . Good starting point.

[wayfastwhitey]

yeah i plan on changing them and then trying it it just seems like it wouldnt be a u joint with all my experiences, but ill try that and hopefully it goes away

[NCHornet]

U joints and carrier bearing would be the first thing I checked. If the truck is lifted and the carrier was never shimmed that is your problem. It is real had to diagnose noises over the internet.

[wayfastwhitey]

there was a rear end put in it so it is possible that that could be it if it was done wrong