Ron Hornaday Jr. and Paulie Harraka got together on Lap 42 and touched off a spectacular wreck that involved David Starr, Brennan Newberry and Russ Dugger.
Newberry and Dugger were evaluated at the infield care center and released.
Hornaday managed to save his truck, sliding through the fourth turn near the wall before getting straightened out down the front stretch. He wound up finishing sixth, while Justin Lofton, Parker Kligerman, Ty Dillon and Miguel Paludo rounded out the top 10.
"We were really good on the restarts and we weren't really good on long runs," Dillon said. "I'm not going to accept it even though it's our rookie year. I want to win."
So does Keselowski, who plans to run four more Trucks races this season.
He led after a restart late in the race, but Buescher managed to chase him down and make the pass on the bottom. Keselowski radioed to his team that he didn't think he had the winning truck, even though there were still 46 laps to go.
Keselowski elected to take four tires when he pitted with 20 laps remaining, hoping to pick up enough track position to have a chance. But the gamble ultimately failed when Buescher, with four fresh tires, easily got around him with 10 laps to go.
"I was kind of worried about the two-tire and four-tire situation, but I knew if we had four tires and came out close, we could probably run them down," Buescher said. "We didn't have to change much on the truck. It was running great."