Weird swaying sound

So, I’ve noticed lately that when I pull out of my garage with the windows down, and my back wheels roll down the 2” or so level change, I hear what sounds like something loose and swaying back and forth immediately after. It sounds like it’s coming from under the bed.

I’ve been under the bed and looked for signs of something being loose but haven’t found anything especially obvious. Any ideas on what this could be, or what to check? This seems to be a fairly recent occurrence.

 

Chain on the Spare?

 

Seems bigger / louder than that, but that’s a good thing to zip tie down and see if it goes away. Thanks for the idea.

 

Float in gas tank? Any other liquid tank in vehicle?

 

Check leaf pack for moaning or squeaking, especially if aftermarket springs.

 

Sit with in the truck w the hood up and have someone rock it back and forth. See if anything is replicated.

 

After listening a few more times, I think it’s actually just my leaf springs squeaking. What made it confusing is that it sounded like it was swaying but I think I’m hearing 2 different things. Anyway, appreciate the help brainstorming.

 

Quick n easy to test, spray with lube or even water and see if it temporarily fixes. I used a water proof spray grease I was gifted, it silences my rear springs,,,,, for a hundred miles