The CMC CCKW, the "Deuce and a half" was the primary vehicle for delivering supplies to Allied forces as they marched eastward after the invasion of Normandy. The CCKW acronym is a part of the GMC model nomenclature: C for being designed in 1941, C for a conventional cab, K for all-wheel drive and W for dual rear axles.
Since Heavy Supply Trucks cannot attack and are defenseless, use Assault Infantry or Submachine Gun to defend them and cover them from enemies and defenses.
Heavy Supply Trucks only heal the closest damaged troop. If you want them to heal a troop that is badly damaged and distances away, try to recall your troops to a safe spot so your Heavy Supply Trucks can heal it.
The A.I. of Heavy Supply Trucks are usually one of the strangest. In some moments on the battlefield, Supply Trucks would run into open fields to get shot at and stay there for 0.3 seconds but would later retreat to start healing troops. This has not been patched by Big Huge Games.
Heavy Supply Trucks and Combat Engineers are the only troops trained in the barracks that cannot be donated to other players.