CHICAGO (AP) NASCAR says Kyle Busch's winning truck in Friday night's race has failed inspection for being too low in the rear.
Any penalties for the No. 18 Toyota will be announced in the coming week.
Busch won his 46th Truck Series race when he pulled away on an overtime restart at Chicagoland Speedway, ending the hopes for many full-time series drivers needing a win to quality for the Chase for the championship playoff.
NASCAR didn't announce any technical issues after the race but confirmed the failed inspection Saturday morning.
Daniel Hemric finished second, joining Timothy Peters as the final two drivers to quality for the Chase.