700R4 Transmission Specificationsby Lindsey Fisher
The 700R4 transmission has been a favorite among performance vehicle owners for years. This transmission can be built to perform easy shift changes for everyday driving as well as for supporting performance cars with 450 foot-pounds of torque. Not always a reliable transmission, the evolution of the 700R4 has created a whole line of dependable transmissions.
Type of Transmission
The 700R4 is a four-speed automatic transmission created by General Motors to put in performance vehicles. This transmission has an automatic overdrive feature that allows cars with high rear-end gear ratios to be driven at highway speeds without problems. Introduced in the 1982 Corvette, it had a 3.06 to 1 first-gear ratio and a 1.63 to 1 second-gear ratio. The drive ratio was decreased by 30 percent compared to other automatic transmissions due to its 0.7 overdrive. This transmission also had a lock-up torque converter and input shafts with 27 splines.
Although the 700R4 had decent specifications, it was a weak transmission that went through many improvements. The first improvement was putting in 30-spline input shafts, starting in 1984. The ring-gear and oil-pump housing were among the internal parts that were upgraded between 1984 and 1987. In 1986 an auxiliary valve body started being put into the transmission. Internal lubrication additions were put in the 700R4 in cars like the Corvette so that the transmission could withstand extreme conditions of high-gear and top-throttle runs.
In 1993 the 4L60E transmission was introduced. At this time, the 700R4 had been switched to the 4L60. The 4L60E is an electronically controlled version of the earlier 700R4s. This version needs a car's computer to control the performance of the transmission's functions. As of 1994, all GM rear-wheel-drive vehicles were being produced with the 4L60E transmission rated at 360 foot-pounds of torque. In 1996, the 4L60E received a transmission case with a separate bell housing that bolted onto the main case. Bigger and stronger transmissions were built off the 700R4 platform in the form of 4L65E and 4L70Es. The 4L65E is rated for 380 foot-pounds of torque. These transmissions provided stronger internals for larger applications like in the Hummer.
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