 For the transmission gearboxes, all IndyCar Series cars currently use an electronically-assisted paddle-shift sequential transmission with a 6-speed gearbox and a pneumatic-actuated clutch supplied by Xtrac Limited since the 2008 season but with assistance.All current IndyCar transmissions use pneumatic actuation for the shifting and clutch.From 1996 to 2007, all IndyCar Series cars used a hand-shifted 6-speed sequential manual transmission with a shift lever, supplied also by Xtrac since 2000 season until 2007.