Cringe worthy grind

There's a horrible noise coming from my back end... I can't watch this again. I cringe every time.

https://youtu.be/uHlpM7JJFhA

This grinding noise is definitely worse when the truck bed is loaded. Barely noticeable when unloaded, but I hear it sometimes when heading up a hill. Pretty consistent 'clicking' that has progressed over the last week to a horrible grind.

Where to start diagnosing?
Rocks in drum brakes?
The rear bearings didn't seem to move too much. That's a $300 fix...
I spent 2 hrs trying to get the drums open on this rusty gem, thinking some rocks or rusted springs or something may be in there.
I guess I'm avoiding thinking about the differential. It's the friggin diff, isn't it...
Any help is greatly appreciated- the more dumbed down the better. I'm a pretty poor mechanic and an even worse truck owner!

 

Cringe

 

I should add... in the video the first reverse/forward is in 4WD. The second reverse/forward is 2WD...

 

Looks like the gas tank shield rubbing on the prop shaft.

EZ PZ

 

Also, why is there a ratchet strap on your gas tank?

 

U got bigger problems judging by ur gas tank dude

 

Gas tank side protection skid (useless light gauge metal) retaining clip popped off. I just chopped that piece off because ive tried various clips but it always pops back out and scrapes the driveshaft eventually...

 

Well thank you Bishop for pointing out such an easy fix! I see now that I should probably trade in the Tacoma for a seat on the short bus.

 

yes that is another problem...

The gas tank strap rusted through, and the replacement strap I installed was missing a couple bolt holes which hold the plastic tank protector/skid plate onto the strap... so the orange ratchet strap is holding the tank protector skid plate up while I figure out this grinding noise business and drill some new holes on the tank strap...

keen observation, AC

 

Tighten up your spare tire too. It's loose.

 

Likely nothing to do with your noise issue, but it looks like the remnants of a plastic bag wrapped where the rear Diff/ U- joint connects.

 

OP is never going to post a shot of his truck online again, lol

 

You found my lucky rabbit's foot!