crazy popping noise from rear end when suspension is flexing. Help!

Did the axel get submerged or the springs wet by chance? Any junk between the leaves or rust can cause a metal popping noise at low speeds. I had similar that sounded like a loose heat shield or something at low speeds.

Try jacking up the rear and supporting at the frame. Let the rear end droop. Clean out between the leaves with a rag or something, then spray some kind of lube in between. See if that helps.

 

Axel has never been submerged.

Thanks for the recommendations.

I'll be jacking it up today and cleaning the ever living hell out of those springs.

 

Looks like what your hearing is the leaf springs rubbing in the two spring clamps as the suspension is moving

 

Interesting close up video. Thanks for sharing that. There is definitely enough binding (ratcheting?) to see it translate to your camera or the exhaust. I hope you get it solved without have to tear everything apart.

 

OP do you have the factory tonneau cover? I have experienced that sound on my son's Tacoma. We folded up the cover so i could ride back there to hear the squeek and it stopped. We found the locking bolt was loose, torqued to spec and that leaf spring squeak was gone!

 

Frustrating to watch, I would want to squat next to a speed bump and try to isolate the source of the sound by listening as someone else slowly drove the truck over it. The video almost surely confirms it’s coming from the leaf springs but where exactly? My vote is still for the suspension being torqued down while unloaded placing improper pressure on the bushings. I would jack it up one side at a time, loosen the leaf spring and shackle bolts, let that side down and then torque to spec.

Could also be a lack of lubricant in leaf spring and shackle bolts.

Not saying it couldn’t also be friction within the leaf springs themselves or with their brackets. Just making my best guess.

 

I second the leaf spring idea. I had a very similar sound on my 2014 regular cab 4x4. A friend who knew "everything" about suspension took a look at it and said it wasn't the leaf springs. "It's in the differential" he said. I went home and cleaned the leaf springs as good as I could in between each leaf with a dry rag. The sound went away.
I don't recommend lube between the leaves because I think in my case I had sprayed the frame with one of those protective coatings (oily) and sprayed the leaf springs as well. I think that is what attracted dirt in there when I went off road.

 

From that last video I think that is the issue too.

To the OP you have aftermarket leafsprings. Stock leafsprings do not use that style of leaf clamps you have. Stock is either very wide or has molded plastic pads where they do touch the leaves.

Before you just hose down and lube everything try lubing just certain areas to pin point the trouble area. I would start with the long spring clamp in the video.

This is a stock spring for reference.

 

I used this product from Speedway motors when I installed my AAL. I figured it would help with any rubbing or binding without using lubricant. So far it works great. The only drawback would be disassembly and assembly of the leaf pack.