General Motors 4T40-E / 4T45-E

General Motors' small transverse four-speed — behind the four-cylinder cars where the 4T65-E went behind the sixes. In the Cavalier, Corsica, Malibu, Grand Am, Saturn Ion, L-Series, Vue and Aura, and the Daewoo Nubira.

It is the 4T65-E's smaller sibling and is very often confused with it, including in parts listings. They share a design philosophy and almost nothing else, so a repair procedure, a solenoid part number or a fluid capacity taken from the larger unit will be wrong.

The failure that dominates it is the 3–4 clutch, exactly as on the larger gearbox, and it presents the same way: a slip or flare into top gear that appears when warm, comes and goes, and then does not go. Catching it early is the whole difference in what the repair costs.

The pressure control solenoid is second, producing harsh engagement or a limp mode, and the input speed sensor third — the latter often taking the speedometer with it, which is a useful tell because it points at a sensor rather than at the gearbox.

The 4T45-E is the strengthened version for the higher-output engines, not a different transmission, but its clutch counts and capacities differ enough that the distinction matters when ordering parts.