Once you find the truck, run to the back. Inside of the truck you'll find cargo bags, like this. The number of bags that drops is random, between 3 and 7 bags. Grav-gun the cargo bags off the truck and open them for its their loot. To open the cargo bags, you must have a lockpick. Use your lockpick on the case and it'll open quickly. Once opened, you'll be notified of what you just found.
Possible Loot
-Money Between $2,000 and $5,000 per bag.
-A New Kevlar Vest This is an uncommon item that can only be found by looting the transport truck. It provides 100 armor.
-Haste Potion This is an uncommon item that can only be found by looting the transport truck. It provides a 30% run speed increase for 2 minutes.
-Health Potion This is an uncommon item that can only be found through looting. It provides 200 health, this is the only way to obtain 200 health.