Performance Automatic makes it easy to swap a 4L60-E overdrive trans into your muscle car

From the August, 2011 issue of Super Chevy / By Michael Galimi / Photography by The Author
Over the past few years, the muscle car population has been indulging in the sweet nectar of modern technology with LS conversions and easy-to-install/tune EFI systems. The blending of new technology has even penetrated the suspension aftermarket as systems (fore and aft) are allowing these same cars to pull unimaginable feats in twisting and turning situations.
Performance Automatic is continuing with the modernization theme with the release of its Super Street 4L60-E transmission and Smart Shift controller. The controller is the company's solution to utilizing an electronically controlled transmission in an older vehicle. The Performance Automatic kit is virtually a plug-and-play setup that allows you to add an overdrive transmission behind a big-block or small-blockłjust add a crossmember and driveshaft.

"Most four-speed overdrive transmissions will have a 25-27 percent drop in rpm when in the overdrive gear and the torque converter is locked up," says Tom Cyr of Performance Automatic. That kind of gear-ratio reduction makes highway cruising pleasurable and increases fuel mileage at the same time. It also allows for a numerically larger rearend gear for those who want more performance but still keep the rpm reasonable at higher cruising speeds. The 4L60-E isn't new to the market, as General Motors brought the transmission to its truck and SUV line-up in '93. This electronically controlled transmission found its way into the Camaro starting in '94 and ended its service run in '02. The aftermarket kicked it up a notch since the 4L60-E needed to be beefed up due to the LS1's power producing potential. Performance Automatic developed its Smart Shift controller so the transmission can back more than just an LS bullet in a late-model Camaro, truck, or SUV.

The 4L60-E, normally, is connected to the factory PCM and controlled by it. The Smart Shift controller, however, changes the situation as it is a stand-alone control box. Cyr explained, "Smart Shift is the latest breakthrough in electronic overdrive transmission control. No laptops or handheld tuning devices are required to have total control over shift points, shift firmness, and torque converter lockup."

The Smart Shift controller allows the transmission to function as a stand-alone entity. Cyr continued, "There isn't a need to download anything or answer any questions. You just install the unit and we include easy-to-follow instructions with a clearly labeled wiring harness."
Utilizing an electronic-controlled transmission has several advantages with the biggest one being the ability to control the shift firmness electronically. There is no TV cable to stretch or offer compromisesłthe 4L60-E can shift smoothly for around-town driving but have hard-hitting shifts when at WOT, something difficult for a cable-operated transmission. In addition to the Smart Shift controller and overdrive gear, the Performance Automatic Super Street 4L60-E package fortifies the transmission for applications up to 550 hp. The technicians install a high-performance 2-4 band, Alto Red Racing clutches replace standard-duty clutches, and a special 3-4 clutch pack.

The pump is upgraded with hardened rings, performance regulator spring, and boost valve. The stock servo is ditched in favor of a performance-oriented one that has a larger surface area for greater holding strength. The last few tricks inside the transmission are valve-body modifications to improve shift feel and transmission longevity. On the outside, Performance Automatic delivers a clean case that has been painted black and finished off with a polished-aluminum pan with drain plug.

The Smart Shift controller is also compatible with other GM transmissions like 4L65-E, 4L70-E, 4L80-E, 4L85-E, 5L40-E, and 5L50-E. Cyr told us that the controller can be used with some of the aftermarket 4L80-E--based five- and six-speed automatic transmissions. The Smart Shift controller is self-calibrating, making the setup process easier as the unit knows idle, part-throttle, and WOT. Cyr concluded, "It doesn't get any simpler. Just follow the instructions and get busy driving."



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