Sound coming from back of truck

Hoping to get some help diagnosing a sound coming from the back of my truck. It only happens when I start driving for the first 30 seconds every morning. I find it odd that after 30 seconds of driving it just stops making the noise. Doesn't happen again all day. Any help would be appreciated.

https://www.youtube.com/watch?v=rZD58NCR9j8&feature=youtu.be

 

rust on the brakes possibly

 

I took it to the dealership a few months back and they said there was some glazing and I had them take care of it. I would think they would have noticed rust. Maybe I am putting too much faith in the dealership

 

Brake drum/discs will develop a light cost of rust overnight in high humidity areas. First time you hit the brakes it's usually knocked off. Living near the gulf coast, it's a pretty normal occurrence. But if yours is making a noise while you're driving, and not braking, it sounds like it's something else

 

I hear a train horn, birds chirping, and what sounds a bit like an oscillating squeal like a dry u-joint bearing cap. If the u joints are good and purge grease from all 4 caps when greasing, lube between the leafs of you rear springs with some sort of spray lube and see what happens.

 

Thanks. Would you happen to know how to tell if the u-joint is bad? Is there more than one?

 

That doesn't sound like a U joint to me, at least not the failed ones that I've heard. My Camry makes some weird noises after sitting all night after a rain, its rust on the rotors. Doesn't sound like yours though.

Tacomas are known to get squeaks in the rear drums that is easily fixed by flushing and cleaning the brakes inside the drums and scuffing the drums, I'd start there.

How many miles? I ran 175K even with towing on my 2006 on original U joints.

 

You gotta beat the rust off them brakes occationally. Drive 45mph and then stomp on the brakes... I garrantee they wont squeek after that!!

 

I got 70k miles on it. This happens every morning for the last month or so. I had the dealership deglaze the drums about 2 months ago.

 

This. It's probably your brakes.