Strange noise in rear end (1 Viewer)

[Vaudo]

I am hearing a strange metal knock sound in the rear end when I reverse and then brake. Sounds almost like something rolling or knocking in the side compartments but, that is not what it is. I have looked under there and tried to get things to move but no luck. Anyone else have this and find the culprit?
I am guessing something in the suspension and would love to solve before snow.

 

[Rusty Marlin]

Spare tire loose?

 

[fjbj40]

Is the sound there reversing only, with brakes not applied?

Loose caliper bolts or pads shifting in housing?

 

[Vaudo]

Is the sound there reversing only, with brakes not applied?

Loose caliper bolts or pads shifting in housing?

I hear it when making turns intermittently, mainly reverse though

 

[fjbj40]

I’d be checking brakes