The History of 4L60e Transmission

GM originally conceived the 4L60 and 4L60E as the TH700R4 four-speed overdrive automatic transmission in 1982. In the early 1980s, GM was desperately looking for more fuel-efficient methods to power its cars after the disastrous 1970s fuel shortages that brought a flood of Japanese imports to North America. Rising fuel costs at the pump and a recession in the early 1980s severely hampered auto sales. The more efficient four-speed TH700R4 replaced the venerable three-speed TH350. The Turbo 700 offered a 30 percent overdrive and had a lower 3.06-to-1 final gear ratio that still provided quick acceleration from a dead stop. Early 1980s versions of the TH700R4 suffered from growing pains as GM worked out the bugs. The automaker was determined to make a success of the four-speed automatic.

GM renamed the TH700R4 in 1990 as the 4L60 to reflect its purpose as a four-speed with a longitudinally placed matching engine and a gross vehicle weight rating of up to 6,000 lbs. The automaker made no mechanical changes to the TH700R4. In 1997, the electronically controlled-shift version became available in rear-wheel-drive cars and two- and four-wheel drive trucks. The sixth-generation Chevrolet Corvette was also equipped with the 4L60E transmission. The 4L60E used solenoids and electronic actuators to control the clutches, valve body and bands to shift gears. GM's Vehicle Speed Sensor and a vehicle powertrain computer determined when gear shifting was optimum. The 4L60E's gear ratios are 3.059-to-1 for first, 1.625-to-1 for second, 1.00-to-1 for third, 0.696-to-1 for fourth and a 2.29-to-1 ratio for reverse.

The 4L6E initially came with the Cadillac Brougham, and as an option for virtually all Chevrolet models. The 1993 and later Pontiac Firebirds and the 1994 to 1996 Buck Roadmaster were also equipped with the 4L60E. GM's Australian subsidiary, Holden, equipped its Commodore and Caprice cars with the 4L60E. The electronically controlled automatic was also available for the 1997 and later Chevrolet Avalanche luxury trucks, Camaros, compact S-10 and Colorado pickups, Silverado pickups, the Suburban, Tahoe and TrailBlazer sport utility vehicles, the GMC Sierra, Sonoma and Yukon, and the Pontiac Firebird and 2004 GTO.

Although GM designed its 4L60E and its older siblings for its own cars, its versatility quickly earned it admirers who owned other makes and model passenger cars and trucks. The 4L60E had become popular as a conversion transmission. A common adaptation is to Chrysler two- and four-wheel Jeeps, and some International Harvester four-wheel-drive sport utility vehicles. Other truck makes equipped with the Dana 18, Dana 20 and the 1980 to 1986 Dana 300 transfer cases can also use the 4L60E.