Introduced in 2005, the C6 Corvette signaled a kind of changing of the guard for Chevrolet's classic flagship. Where the C5 was a something of a much-loved holdout that spit in the face of deliberately technical European supercars, the C6 was a definite step up into that league. The subtle difference between its transmissions is testament to that little bit of extra thought GM put into making the C6 a true world-beater.
The C6 used two basic transmissions: the 4L65-E four-speed automatic, and the T56 six-speed manual. The 4L65-E was an evolution of the 700-4R from the 1980s, which itself was an evolution of the musclecar-era TH350 three-speed auto. In the Corvette, the 4L65-E used a 3.06- first, 1.63- second, 1.0- third, 0.70- fourth and 2.29-to-1 reverse gear feeding a 2.73-to-1 final drive. The regular six-speed manual used a 2.66- first, 1.78- second, 1.3- third, 1.0- fourth, 0.74- fifth, 0.50 sixth and 2.9-to-1 reverse, with a 3.42-to-1 final drive. GM also offered an electronic -- "manumatic," or "flappy paddle" -- version of the T56 that used a "skip-shift," first-to-fourth-gear function for a boost in fuel economy. For this reason, its first-though-third gear ratios are a little bit higher, to get them closer to the fourth gear's 1-to-1, and the final drive ratio is a little bit lower to "stretch" first gear's speed range into fourth gear's. It's ratios were 2.97- first, 2.07- second, 1.43- third, 1.0- fourth, 0.71- fifth, 0.57- sixth, and 3.28-to-1 reverse. The flappy-paddle box fed a 3.15-to-1 final drive gearset.