General Motors F-series (F17 / F23 / F35 / F40)

General Motors' European manual transaxle family — designed at Opel and fitted across the company, from the Astra and Corsa to the Cavalier, Cobalt, HHR, Grand Am, Saturn Ion and Vue, the Saab 9-3, the Cruze, the Cascada and the Chevrolet Aveo.

The family is the point, because the members are numbered by torque capacity rather than by generation. The F13 and F17 are the small ones, the F23 is the American five-speed, the F35 its Saab-bodied cousin and the F40 the six-speed for the higher-output engines. A gearbox is chosen for the engine in front of it, not for the model year, so two cars of the same name and year can carry different members of this family.

Its recurring complaint is bearing noise rather than failure. These gearboxes whine — some from new — and the useful distinction is when: a noise present in neutral with the clutch out and gone when the pedal is pressed is the input shaft bearing, while a noise that changes with road speed and not with gear is a wheel bearing or a driveshaft and has nothing to do with the transmission at all.

The F40's own theme is the differential, which is the part the six-speed's extra torque finds first.

Shift quality complaints are usually the linkage. The cables, their bushes and the base-plate bushings wear, and the result — vague, long, occasionally refusing a gear — is read as a worn gearbox far more often than it is one.

It is a family and its members do not share a speed count. The F13, F17 and F23 are five-speeds; the F35 and F40 are six, which is what the Regal, Cascada and Cruze carry. A ratio or a part number quoted for the F-series describes one of them.