design thus eliminated the need for drive belts to power the tractor forward or backwards. The only belts required on Gravely equipment (with the exception of the 408) is the blade drive belt for its mower decks, which is powered by a gear box on the deck, which receives power from a PTO driveshaft connected to the tractor's drivetrain. The tractor's direction is controlled by a lever to the right of the operator for forward, neutral, or reverse operation. Because of this, this tractor is often mistaken for having a hydrostatic drive. In 1965, Kelly G. Cunningham used the Gravely 7.6 tractor to create the Terramite Model 1 compact backhoe, now known as the T1. In 1967, Gravely introduced its 400 series riding tractors, with the all-gear drivetrain that would come to define the company in future years. The tractor had four speeds, two in low range and two in high range, with power configurations of single-cylinder 10, 12, or 14 horsepower Kohler or Onan engines. In 1969 was the debut of the 16.5 HP Onan CCKA twin-cylinder powered Commercial 450, the most powerful tractor the company offered at the time. The commercial-grade units were painted a characteristic yellow and white, while the home-use units were painted red and white. The 400 series was produced until 1971, when Gravely introduced its replacement: the 800 series tractors, which gained popularity in the consumer market. This tractor had eight speeds, with four speeds each in low and high range, with engine options ranging from a cast-iron 10 horsepower Kohler single-cylinder, to an 18-horsepower cast-aluminum twin-cylinder Onan. The 800 series was replaced with the 8000 series by 1978, which offered more powerful engine configurations and an improved hydraulic lift option, yet retained the eight-speed transaxle. Many of the parts for the 800 and 8000 series designs, excepting the engine, are the same or compatible, and are readily available as new and used parts online, in a rather impressive after-market. The 8000 series remained in production until 1987, when it was replaced by the professional-grade "G" series. The G series ended production in 2004. The eight-speed transaxle was standard on all 800 and 8000 series tractors, with the engine being the only major difference. The design of the drive clutches was visibly changed to a simpler arrangement around the early 1980s; the two designs are generally interchangeable. The rear-engine mounting and simple construction allowed