General Motors 9T50 / 9T60

General Motors' transverse nine-speed — in the Malibu, Blazer, Acadia, Terrain, LaCrosse and the Cadillac XT4 and XT6.

Most of what is reported about it is the ratio count rather than a fault. Nine gears in a front-drive family car means the transmission changes constantly and hunts between the tall ones on a light throttle, and it holds a very tall top gear at low speed. That is behaviour, and comparing against another example of the same model settles it faster than any scan tool.

Its own recurring complaint is a hesitation or a shunt from low speed, typically when rolling back onto the throttle after lifting — the transmission is deciding between two nearby ratios. It responds to adaptation and to software far more often than to parts, so a relearn and a check for a transmission control update come before anything else.

The torque converter and its lock-up clutch are where the genuine faults cluster, presenting as a shudder at light throttle, and — as on every recent GM automatic — fluid condition is the first thing to establish rather than the last.

It is not the 9T65 of the heavier crossovers, and it is not the 10-speed longitudinal. GM's transverse and longitudinal families share a naming convention and no parts.