I have a 2000 F-350 Power Stroke with 4.10 rearend. The owner's manual says 10,000 pounds towing capacity. Doesn't sound like much today, but back then it was considered quite a bunch.Trying to determine 5th wheel towing capacity of my ‘19 F250 P/S with 3.55 rear. Have been told everything from 18000 to 14000. Help. I’m confused.