Can someone here help me identify what is going on with my truck. 2021 f150 , 55k miles, purchased new. Hearing it when slowing down or backing up driveway. Frustrated as ford service department keeps the vehicle for days, says we can't replicate and returns it. I hear the sound literally pulling out of the dealer and driving home. Even took the tech for a spin and he heard it and they lubed the calipers and said they could not replicate it. It's TSB 21-2253 this issue or something else. Going to bring it up today with them.

https://youtube.com/shorts/RqmSsV28Ty8?si=5Esk7AmGoJm5Fq_C

 

Maybe it's this SSM I attached. Without your VIN I can't verify your vehicle is equipped with these EPB calipers.
Hopefully that helps

 

My truck is making the exact same sound. Did you ever find out what it was? I have not taken to the dealer yet but yeah they are trained to say they can’t hear it. I will go from 1 to 10 in about 5 min if they play this game. I haven’t had this truck 9 days and this crap is happening.

 

This may fix your issue. Had same issue with my 2015 Lariat Supercrew. Common as the factory ones wear out at an early age. Haven't had the issue since ordering and installing back in 2021

2015-2020 Ford F150 Leaf Spring Outer Isolator Bushings (atqauto.com)