Hello all, I'm new here. I'm usually a Jeep guy but I recently acquired a 2000 Ford f150 with the 4.2 v6.
It seems to run good but there is a persistent whine, but only on acceleration. I have a video I could link.
Could it be the transmission, wheel bearings, rear differential....I'm going through it with a fine toothed comb.
I'm re building the rear drum brakes. The pad lining fell out when I removed the driver's side drum.
I'll replace the fluid in the rear diff and do a tranny filter and fluid change. I'm hopeful one of those things help.
Any Ideas?

So I have done a trany filter change and dex V ATF change and the whine is gone. I'm so relieved. I hope this information helps someone else in the future.

 

 

I do not believe that is the differential as that whine drastically changes with engine RPM when the tranny is shifting.. The diff. would change very gradually. Sounds almost like alternator whine in the sound system to me. If you ruled that out, start looking at tranny or something under the hood. This is very difficult to tell from a youtube video.

 

It might be the alternater, I'll check it with the screw driver to the ear trick, in the video I turned the radio off. I hope its not the transmission. I put it up on 4 jack stands and started and accelerated in dvive but the noise was not present, could that mean that it has to be under a load to whine....

 

Start at the front by taking the serpentine belt off. Spin by hand each idler pulley, tensioner pulley, fan, alternator, etc. Listen and feel for roughness.
Also check the level in the power steering pump reservoir. A cavitating pump really whines up too.
If you don't find anything up there, work your way through the systems towards the back of the truck.

 

Thanks for the Ideas, I'll look into it.