Rear (brake?) rattling sound

Hi y'all,

*2012 Tacoma 4x4 4cyl MT*

Pulling into my gravel driveway tonight I heard a loud hollow rattling from what sounds like the rear left wheel area. Sounds almost like a tin can dragging in gravel but I got under the truck and nothing looks or feels loose. I did look at the inner RL wheel and saw some loose flakes of rust (I'm in Vermont - there's some rust...). I'm not sure how useful an indicator that is though.

First thought was spare tire chain or leaf springs but those don't make any noise when I test the suspension with truck off and parked. Sound happens when I roll forward or backward, both in neutral and in gear. Calipers? Ebrake?

I made a video to capture the sound. First I roll backward in neutral, then pull forward in gear, then repeat. The sound is pretty obvious.

Let me know if this sounds familiar. Thanks.

 

Raise the rear axle (chock the front wheels)
Put the truck in neutral, and spin the tires.
See if you hear the noise, then pull off the brake drum and look.

 

^^^^ That would be my next move before driving it anymore...

 

Did you ever figure this out, i got this same exact issue after replacing my diff. Sounds exactly the same. Coming from my LR drum brake

 

I’d to this.

It’s hard to say without looking. Could be excessive brake dust, a backing plate bolt came out, a spring that’s broken or came off or installed wrong. Ya gotta look.

 

I didn't have a way of lifting the truck at the time so my mechanic took a look and said it was just built up rust on the backing plate that came loose.

 

So he just cleaned it up and problem solved ?

 

I guess so - I didn't see what he did but it took about half an hour max...

 

That’s great. No parts too, except for maybe some brake cleaner. I always forget to consider taco rust.