I came across this post and had the same issue with my 2022 Chevy 2500 custom. I’ve always used fluid film and it’s saved/preserved my trucks in the past. Figured I’d share my experience with the new one. A few days after the application I started noticing the “clunk” at low speeds around corners and unlevel ground. The leaf spring bushings also creeked when you jumped on the rear bumper. Here’s what I did to fix. I jacked the truck up by the trailer hitch until the rear wheels came off the ground. I simple greened the crap out of the leaf spring bushings and the leaf ends where the plastic pieces are present in between the leafs. I then power washed these areas. Be careful. Don’t get too close or you’ll blow the undercoat off! Test drove it after. Didn’t seem to help. I then jacked it back up again and sprayed silicone lubricant on these areas, and what do you know? Back to being quiet again! It’s been about 2 weeks and still quiet! Hope this helps! I was nervous for a while that my brand new truck had permanent damage. Going forward I’m just going to avoid these areas with FF on next years application.
