The 66RFE transmission is a 6-speed automatic transmission that was first produced in 2012 for the gas engine Ram 2500 and 3500 trucks. The 66RFE transmission is considered to be a hybrid of the 68RFE and 545RE. The 66RFE transmission uses a 545RFE case but contains many of the same internals and gearset as the 68RFE. Raybestos Powertrain offers premium 545RFE friction materials and parts like the GPZ friction clutch plate to handle more power and provide greater durability beyond OE friction material capacity.