Porkchop first appears in AcceleRacers: Ignition driving this semi into the Acceledrome. On the flat-bed trailer he's hauling Jack Hammer, Rollin' Thunder and Rivited.
In Breaking Point, the truck has a tanker trailer filled with Nitrox 3 1/2. Monkey has equipped the rig with Nitrox boosters and an EDR for use in the Racing Realms. The new wheels (reverse engineered from the Racing Drones') also have been equipped on the truck - you can spot the red dots on the hubs in a couple of scenes.
Monkey and Porkchop take the rig into the Junk Realm in order to combat the Sweepers threatening their Metal Maniacs teammates. The rig is destroyed, but takes two Sweepers with it. Monkey and Porkchop return via the EDR.