If you look on pg 17 of your 'tow guide' you will see on left side
6.0L V8
Turbo Diesel
Then follow it across chart to Reg cab ---- Super Cab ---Crew Cab and which one of the DRW options 4X2 or 4X4
Ex: Super Cab DRW 4X2 Auto Trans
16,300 MAX GVWR 5th wheel
Now that 16,300# is the MAX based on the fine print
Trailer king pin weight should be 15-25% of total loaded trailer weight. Make sure vehicle payload (reduced by option weight) will accommodate trailer king pin weight and weight of passengers and cargo added to the towing vehicle. Addition of trailer king pin weight, and weight of passengers and cargo cannot cause vehicle weights to exceed rear GAWR or GVWR.
These ratings can be found on the vehicle Safety Compliance Certification Label.
So 20% of 16,300# ---- 3260# for 5th wheel wet pin weight
That is what has to be carried by trucks rear axle
W/o causing truck to be overweight Either GVWR of truck, RAWR or Rear tire Max load ratings
A 2005 DRW is very capable tow platform for a 16,000 GVWR 5th wheel
I have a 2007 SRW and tow 14K 5vr