Clatter/Clacking noise when under heavy load (accelerating or decelerating)

My 2007 4.0 V6 with 6 Speed transmission recently developed a weird noise coming from the rear half of the truck (I think).

The sound is a clatter, rattle, clacking noise (not sure how else to describe it lol). It also occasionally gets a whirly squeal, a noise I heard before replacing my uJoints about 35,000 km ago. Both noises only happen when accelerating or decelerating, more predominantly up or down hill. If I put the clutch in, the noise seems to go away.

I'm leaning towards replacing the uJoints again, but I'm curious if anyone else had a similar issue. I'd like to avoid replacing random parts right now.

Side note: I don't think it's coming from the clutch, I've had the throw out bearing squeal/chirp before and the noise doesnt seem to come from up front like before.

Thanks!

 

It sounds like u-joints to me. Are the ones in it now greaseable? If they are, grease them and go for a drive. If the sound changes, it's likely the source.