Loud clunk noise after truck would not reverse

Hi all, I went to wash my truck today. As I always do, I tried to spend a minute or two washing the frame to get any debris/salt off. It’s about -10C where I live right now, so I parked it in the garage overnight to make sure it could dry out.

I shut off the truck to go open the garage door, then started it up again. I put it in reverse, and gave it a little gas. The engine revved like I was still in park. I figured maybe I just wasn’t giving it quite enough because my garage is on a slight incline. I gave it some more gas, and the truck jumped back and made a pretty loud CLUNK sound that spooked my wife and I pretty good.

I have to think this has something to do with ice buildup from washing the truck, as I’ve never experienced this before so the timing is suspect. Any ideas what it could be?

Thanks!

EDIT: I should also add I was in 4HI at the time.

 

Brake drums are frozen to the shoes. Drop it into 4 high and carefully pop it into forward then into reverse and then give it some gas until they break free or pull the wheels and heat the rotors up with a torch until the ice melts, then immediately put the wheels on a drive it before they warm to dry the water inside out.

 

100% agree the drums are frozen up. I usually break the shoes free of the drums after washing by a few slow but firm pushes one the brake pedal. They rust onto the drums down here in FL… assume the same would help if they are legit frozen brrrrrr

 

as mentioned, most likely rear drums.
Did you set the parking brake?
Don't do this after wash.

 

I did. This is good to know, silly of me. Think there’s any chance I damaged it? Or how I could tell?

 

nah, it’s fine, it popped loose, it’s the pads sticking.
It’s not silly, this part of the truck is silly that it sticks, but an easy thing we can get past.
Enjoy your truck and your holidays!!