How many bump stops under bed of Ford F-350 Super Duty?

Hello, I'm not sure what you're asking. If you have a knocking noise, it'll be necessary to have a physical inspection performed of your vehicle to figure out what is making the noise. Keep in mind that you might be hearing normal suspension travel, but you could also have something loose or worn. Use this link to find some shops near you that can help with your concern: www.repairpal.com/repair-shops