The truck has a dump bed manufactured by Converto.

“Very Rare 1948 Willys Dump Truck all original frame-off restoration. This truck was originally sold as a cab & chasis and sent to Converto Mfg Co to install the dump bed. The dump is operated by a manual hydraulic pump located in the cab. The truck has the stock original 4 cyl motor and manual three speed on the column transmission.

Everything works correctly and the truck runs and drives like new. Please let me know if you have any questions or would like more information about the truck”

https://philadelphia.craigslist.org/cto/d/1948-willys-dump-truck/6253719436.html