![]() ![]() ![]() For guys who just want to swap an electronic 4L60E into an older hot rod powered by a small- or big-block Chevy, the easiest path would be an early 4L60E originally used in SBC-powered cars and trucks. ![]() There followed a fourth and most recent 4L60E evolution that accommodates an input shaft reluctor that does not effectively interchange with earlier converters.īecause LS engine swaps into older muscle cars has become a foundation in the performance world, this means the 4L60E is heavily ingrained in this parts dance. With the introduction of the LS engine family in 1998, later 4L60E transmissions employed a third different input, also 30-spline, with a larger 300mm torque converter that is substantially thicker (about ¾-inch) than previous versions. Later 1984-’97 700R4 and 4L60 versions were of the 298mm family line, with a 30-spline input and a 1.70-inch diameter hub. For torque converters, the earliest 700-R4 transmissions used a 27-spline converter. This move allowed adapting multiple engine bellhousing patterns to the same case. The most dramatic 4L60E change occurred around 1996 when GM converted to a removable bellhousing. The next major change was a six-bolt extension housing in 1993, compared to the original four-bolt. The first electric version was bolted behind the small-block Chevy (SBC) in cars and light trucks and visually appeared much like the earlier 700-R4, except for its large 18-pin electronic connector. The 4L60E has now been in production for more than two decades and has experienced multiple performance updates that affect interchangeability. Later transmissions were upgraded as 4L65 and 4L70 for use in heavy-duty trucks. The numbers decipher like this: 4 is the number of forward gears, L (longitudinal) for rear-wheel drive, 60 equates to a maximum 6,000 pounds of gross vehicle weight (GVW), and E for electronic control. In 1993, GM wisely converted to electronic control, eliminating the cumbersome TV cable while changing its nomenclature to 4L60E. Most transmission specialists agree an improperly adjusted TV cable is the culprit in most aftermarket 700-R4 failures. This first version was designed with a bolt-on extension housing and employed a throttle-valve (TV) cable intended to signal engine load to the transmission via throttle position, instead of a using engine vacuum. Third gear is 1:1, with overdrive again engaged to create Fourth. This gearbox is different because it applies an overdrive to First gear to create Second. ![]() The original 700-R4 was built in 1982 as a Corvette four-speed automatic with overdrive. We’d also like to thank Jimmy Galante at Racetrans in Sun Valley, California, for his technical guidance with this story. We’ve done the research so you don’t have to wade through all the inaccurate chaff to pick out the seeds of the best 4L60E. This story will look at the evolution of the 4L60E, which is essentially a digitally controlled 700-R4. If you look at the progression of new cars for the last 30 years, it’s all about digital management of every aspect of the automobile - including automatic transmissions. The automotive world is increasingly regulated by digital electronics, and hot rodders might as well take advantage of these amenities. ![]()
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