A Fuel Efficient Automatic Four-Speed Transmission for Light Trucks

One phase of the broad General Motors program to improve fuel economy has been the design of an integral 4-speed automatic transmission that improves mileage in light trucks. This new overdrive unit features wide ratio gearing with 4-speeds and reverse from 2 planetary gear sets, a cpnverterclutch assembly, a variable capacity oil pump and extensive use of aluminum. Unique construction of several components produces a compact transmission that weighs only two pounds more than the 3-speed unit it replaces.