 FACT: On standard truck winches, like the WARN winch used on the  Dodge truck, the manufacturer recommends that at least five complete  wraps of wire remain on the drum as the minimum to make a safe winch  pull. So if the winch cable "ran out" as it did in the scene, as the  truck started to get pulled, the only thing holding the winch cable  onto the winch drum is a small bolt. If the weight of the vehicle is  applied to that small bolt (versus the other end at a static  object), the winch cable would snapped off.