I believe that's Snowman's truck. In this movie he pretends to be the Bandit so he's only shown driving the truck for a short period at the beginning so it doesn't really contribute to the movie.
There aren't many trucks in this movie. I do remember a convoy scene in it though, where the Snowman drives up under a rig to hide from Sherriff Justice, and it tears the antenna off the car. Most of the chases in the movie just involved the Snowman in the Trans Am getting chased by Buford T. in his Bonneville, and then Buford T would run into something, until he caught up to them again.
It was kind of a fun movie, in a mindless sort of way, but a definite step down from the other two. I think the best chase scene was when Buford got into a little jurisdiction battle with a local yokel in a '76 LeMans enforcer. The LeMans ends up creaming a Vega alongside the road and ends up soaring into the air, doing a pretty impressive roll.