in 2001. He also added three other Top 10s, and won another pole at Fontana in addition to starting in the Top 10 for half the races. After finishing 17th in points, he left the team. He made his Truck Series debut that year at The Milwaukee Mile in the No. 4 Dana Dodge Ram for BHR, but exited early due to a transmission failure. He also ran three races in the No. 33 Oakwood Homes Chevy for Andy Petree Racing as a teammate to his father, filling in for the injured Joe Nemechek. He also ran seven Cup races late in the season for Morgan-McClure Motorsports, driving the No. 4 Kodak Chevy to three Top 20 finishes. 2002–2006 In 2002, Hamilton joined Team Rensi Motorsports to drive the No. 25 United States Marine Corps-sponsored Ford Taurus. He won his first career race at New Hampshire and finished eighth in points. He also had his first Top 5 finish in the Truck Series at Nashville Superspeedway, finishing seventh in his father's Square D entry. He had his statistically career-best season in 2003, where he won four Busch Series races and finished fourth in the final standings. He also partnered with Rensi to run some races at the Winston Cup level, his best finish being a 14th at Kansas Speedway in the No. 35 Marines Ford. Hamilton returned to Rensi in 2004, but did not win a race. He competed in six Nextel Cup events for Phoenix Racing in the No. 09 Miccosukee Indian Gambling-sponsored Dodge, and had a best finish of 17th. He also drove three times in the Truck Series, winning a pole in his father's No. 04 truck, as well as running twice for HT Motorsports. After 23 Busch races, he left Rensi to move up to the Nextel level, driving the No. 32 Tide-sponsored Chevrolet for PPI Motorsports. He was given the full-time ride for 2005, but struggled immensely, failing to qualify three times and not finishing any higher than 11th. After driving two events in equipment leased from Front Row Motorsports, Hamilton was let go from PPI at the end of the season. Without a full-time ride, Hamilton moved to the Truck Series, leasing equipment from the No. 08 team owned by Green Light Racing, and running with Corky's Ribs and BBQ sponsorship. After three races, it was announced that his father had been diagnosed with