In the opening, he doesn't catch up with the truck. Then the main story of the movie takes place, and it's a story of redemption of
some sort. The movie ends with the same sepia-toned flashback, except this time the truck stops, and he climbs on the back with the other boys. Seems like this was a fairly popular movie, I just can't remember what plot goes with the flashback opening and closing.

I found it. Savannah Smiles.