Edit: new video in second comment.

 

Here's another video I just took. You can hear the sound much better. I'm hoping it's the u joints as that's what I'm going to replace.

It doesn't make the sound when I lift up the rear and spin the wheels. The caliper seems to be free and not sticking at all. I've even driven with the e brake slightly depressed and it still makes the sound. I've never heard a bearing squeak, only hum and I didn't notice any play.

Any thoughts on this sound?

New video

 

Bump.

 

Good theory. It's very possible esp if they've never been greased.

 

Yep. 115k on them. Never been greased.

 

U-joints usually have a fairly rythmic squeek that is directly related (in frequency) to vehicle speed. I'm not saying it's NOT a U-joint, but doesn't sound like one to my ear. Another giveaway is a ping or a pop when alternating from drive to reverse.

 

If you don't think it's a u joint, do you have an idea of what you think it could be?

I've listened through a lot of videos of bad u joints. And yes, I agree most do have the rhythmic squeak to them. But I did also find videos that sound like mine. Maybe mine is just starting to go bad and not yet consistent? I'm not trying to convince you, I'm just really unsure.

Also, the pop or clunk, wouldn't that be slip yoke related?

I'm just trying my best to diagnose but this is so intermittent that I can't get it to do it on a lift.

I also don't want to throw parts at it.

I just don't know what would squeak like that in the rear besides a u joint?

 

Could be rear brakes. Keep in mind that you have drum brakes as your emergency brake, and disks for driving brakes. It really sounds like brakes to me.

 

If it's brake related, I'd go for the E brake over the actual brakes. I just put on new rotors and pads back there recently and the calipers seemed fine.

The E brake does not hold the truck in reverse and has never been serviced. I was going to have that fixed at the same time. Maybe I'll do that first and see if the squeak is still there.

But, I did slightly apply the E brake and drove. It did still make that sound that's why I figured it wasn't related.

I guess there could be a spring or something in the drum getting caught up.

Thanks to all for the input so far!

 

If you pull the shaft and swing the joints by hand, you'll have your answer pretty quickly. Or you could post a couple good close up photos of them. They usually have some visual tells.