SoylentNews

Like the old 6-speed units, which GM refined over the years and expects to continue applying to its vehicles into the near future, the 9-speed was developed through a partnership with crosstown rival Ford.

Both automakers also derive 10-speed variants from the work. Ford brought that gearbox to market recently in the F-150 large pickup, while GM got first dibs on the 9-speed. GM's first application of the 10-speed will be in the '17 Chevy Camaro ZL1, a 640-hp supercharged version of the sports coupe due later this year in the U.S.

[...] In-house logics software inside a 32-bit transmission control module handles all shift events for smooth, precise ratio changes, GM says. It also monitors transmission performance and compensates for wear in parts such as the clutch plate to maintain consistent performance over time.

"This transmission shifts very smoothly, very precisely," Kline says.

The controller is mounted outside the gearbox to reduce packaging and manufacturing complexity, and it pulls vehicle-specific calibration from the cloud to be added to the core program as the car or truck exits the assembly line. It also enables manual shift control and grade logic, GM says.

The 9T50 features a wider 7.6:1 overall ratio, compared with 6.0:1 in its 6-speed predecessor, a deep 4.69 first gear for off-the-line performance and a tall 0.62 top gear for fuel-efficient, low-rpm highway cruising and optimal NVH.

Sixth gear is equivalent to eighth gear on the new transmission, too, so compared with the 6-speed the 9-speed offers two fuel-saving overdrive gears. Seventh gear is the direct-drive gear, while ninth gear is in use up to 52% of the time.