I have a 2000 F-150 XL with a 4.2L V6 manual transmission and roughly 100K miles with a squealing sound.

The sound is only at idle or low RPMs but not constant. It fades in and out sometimes but when I accelerate it goes away.. I thought it might have been and idler pulley so I changed one yesterday and I thought I had it. I let it run and was talking to a neighbor when a few minutes it started again so I with the transmission in neutral and the engine running I slid under the truck. The sound seems like it's coming from the transmission area. I've had the truck 5 or 6 years and have never changed the transmission fluid but it's in neutral so I wouldn't think it's really the transmission making the noise.

Any clues out there?

 

It might be the pilot bearing - is it ever a bit balky trying to put it in gear?

 

I had another brand that did that. Turned out mine was the needle bearings in the end of the input shaft, I had neglected service too.

Drain the fluid and see what comes out.

 

No problems or anything out of the ordinary shifting gears. I do have some other noises or rattles like something is a little loose sometimes but the're not squeals. I'm wondering if I just have something a little loose and it's a high pitched vibration noise. I can't tell if it sounds like it's spinning or could be a vibration. I thinking it's a spinning type noise.

 

Well - you do have either a clutch or tranny issue.