So some background on this lemon so if someone has any advice they have all the facts. Since the day I have had this truck I have had a noise, it's rotational and is related to rpm. I have done many things to try and get rid of it and had many issues that have over shadowed this but it's now at the forefront and driving me nuts. Yesterday I had a really bad noise coming from the back end near the rear dif, I replaced the u joints, it resolved the super loud noise but not this original noise I was trying to fix. Last year I replaced all the breaks, 4x4 hubs, entire 4x4 vac system and rebuilt the motor. I have been able to diagnose and fix every issue this thing threw at me except this.

Does anyone have any advice it's been doin this for about a year.

 

What year is the vehicle and what power train are you running?

 

07 F150 4x4, noise is regally apparent but for some reason we haven't been able to pin point it as of yet.

 

what kind of noise are you talking about?

 

I bet its either your rear pinion bearing or axle bearings. Does it stop when you let off the gas?

 

There was a noise that was really bad under acceleration, I replaced the u joints and it went away but I still had another noise. It's based on speed so at low speed it's slow and subsequently faster at high speeds up to around highway speed and then I can't hear it. The noise comes and goes. What's the best way to check of its the rear pinion bearing or if its the axle bearings?