The GM 5L40-E transmission is one of the GM (General Motors) entries the open record knows by name and by date — in 1998, and by little else. That is not nothing: a name in the catalogue is where a car's story starts to be recoverable.
How it came about
The 5L40-E (and similar 5L50) are a series of automatic transmissions made by General Motors. Designed for longitudinal engine configurations, the series includes 5 forward gears and is used in the GM Sigma platform vehicles from Cadillac, the Pontiac Solstice, BMW, and Holden Commodore. The electronically controlled transmission is designed around a fully articulated Ravigneaux planetary gearset that is controlled by electronically timed application of several range-specific hydraulic clutches, in combination with mechanical one-way sprag clutches.
The 5L40E unit's centerpiece is an automatic overdrive which supersedes the French-made 4L30E four-speed automatic light-duty gearboxes, and like them features a torque converter clutch to eliminate slipping losses in select forward ranges. It is assembled in Strasbourg, France. The 5L40/50 series was replaced in 2007 with the 6L50 six-speed.
Family and rivals
Its family tree is legible: it took over from the 4L30-E / 4L60-E/4L65-E; its successor was the 6L 45 · 6L 50. Its contemporaries in the catalogue — the Lexus IS, the Chevrolet Silverado, the Cadillac Escalade — show what else the money bought that year. Its GM (General Motors) stablemates include the 1955 Chevrolet and the 1957 Chevrolet.