Chatter that can't be fixed/diagnosed

TL-DR: I have a very loud chatter coming from my truck under braking. All new brake components have been installed. No clue what's making the sound. 2003 Tacoma SR5, 4x4, v6 manual.



I need some help and/or ideas from everybody. Here's the story, as brief as I can make it:

1. Pops and I decided to upgrade the front brakes to Tundra brakes. At the same time, we put on new rear shoes and drums.

2. Braking wasn't great, but better. Upgraded my engine and trans mounts to solid.

3. Developed a "chatter" that sounds like it's coming from the rear end. It only happens under heavy braking. Downshifting doesn't do it, rolling to a stop doesn't, only braking.

4. Buddy thought I might have misadjusted the drums, so I took it into a decent shop. They dug into it and found some issues from my install job, did some work on it, and gave it back. The braking was worlds better, but the chatter was basically gone for about a day. They've taken a look twice at the rear brakes (and full system) and don't see anything wrong to cause the sound.

5. The same shop, way before this issue (just a check up), stated there was some vibration from the rear bearing of the driveline that I should address at some point. They dont do that specific work, so they recommended me to a driveline shop.

So, now I have my truck, brakes work great, but a very loud chatter from the rear every time I brake. It almost sounds like a quieter Jake Brake.

Thoughts on this being related to driveline vibration? My next steps are to go back to OEM mounts and then potentially pull the driveshaft and bring it to a specialist. OEM mounts might or might not be related, but the wife will be happier anyway, and its a cheap update.


Thoughts on what this might be?


*Some thoughts/ideas so far:
1. Axel wrap (very unlikely)
2. Out of round rear drum (wouldn't the shop have sorted that?)

 

Video?

 

I'll work on getting a clip of it. Might be a day though.

 

YouTube has a vid or two that might cover your issue. Are they aftermarket shoes/drums?
Reason I'm asking is sometimes the shoe material isn't beveled correctly at the edges, and as the drum turns, the edge of the forward brake pad contacts the drum. Its not a smooth contact and the pad actually bucks against the drum surface. If you look at the top edge portions of the brake pads compared to the bottom edges, should be more of a bevel at the tops. Just did my 02 Taco, Previous owner had aftermarkets on, could move backwards fine, go foward brief chatter and lock up. Turned out it was the brake shoes, replaced with OEM drums/shoes works fine now.
Just my experience, may, or may not solve your problem.

 

Turns out it was a drum that was out of round. Really wish I would have pushed on the first shop harder to inspect that but live and learn. She's back and had the LCA's replaced at the same time, so feeling good about that.