mine goes in for new driver side leaf spring this week, the bushing squeaks and is not sold separately

 

i have this too, guess i will take it in

 

I've had the same problem. I just turn up my radio. If it gets really bad I'll take it in.

 

I've had my truck for just over a year and heard a similar noise from time to time mainly on rough roads etc.
Turns out it was my spare tire creaking against the frame so I lowered it and put some stick on rubber strips on the frame rails and all has been fine for months. Check that the lift winch hasn't loosened up a bit. That happened twice while off roading. Just enough that the spare would rattle a bit.

 

After going to the beach (Outer Banks in NC) I noticed several squeaks developed. Doors, tailgate, etc. The salt water air and hinges didn't play well together. A little white lithium grease had me back to quiet. Not saying it's your issue, but it is my $.02. Good luck!

 

I had a similiar issue and it only occurred when the truck rocked and not when I both rear wheels went over a bump at the same time (like a speed bump). My truck was like this the day I picked it up and when I asked the service dept to check it they were able to identify the rattle immediately and fixed the issue. The dealer had to torque both rear shackles, lube the suspension and now it's fine.