From my understanding, the rust on the undercarriage is normal. However, does anyone know what the white material is in the pictures? Feels almost like fabric. 2023 with 1,500 miles.

 

Looks like something got misplaced during manufacturing when they coated the differential housing. The manufacturer (likely not Ford) was lazy and cut away what they could. I’m surprised that the Ford assembly line didn’t notice it - definitely a manufacturing escape. That said, I can’t see how this would affect fit or function.

If the truck is new and under warranty, the dealer should be able to find a way to remove. If it were my vehicle, I would scrape it off, apply rust converter, and spray the area with rust oleum.

 

My 23 had paper towel type stuff hanging off there when I got it, it was stuck to the same spot and I pulled it off. I thought it was strange but didn't think much of it. To see you have something similar is interesting.

 

Looks like the end of the part was not to be coated so that may be a remnant of whatever was used to mask it off.