I just bought a 2020 1500, and it comes, paid by the dealer, lifetime power train warranty, which requires recommended PM’s to be performed. But I requested a MAXCARE plan good for 75K miles. So I’m covered to 104K miles (don’t remember time line). So the 3rd party warranty doesn’t start until the time expires, doubt it’ll expire by mileage. Purchased from a Ram dealer, someone installed air assist springs, they weren’t aware of when they sold it me, more than likely, I doubt it’ll affect my engine transmission and electronics side of the warranty.