Type: transverse front wheel drive, five-speed manual transaxle.
Engine Range: 2.2L-2.4L
Max Gearbox Torque: 170 lb.-ft.
Weight: 102 lbs.
Applications: Chevrolet Cobalt, HHR; Pontiac G5
The Getrag F23 is a three-axis conventional transverse five-speed manual transaxle with fully synchronized reverse gear. It features compact packaging, broad low-torque applications, and reliable operation.
The F23 has two gearsets on each of three parallel shafts – the input shaft, the output shaft, and the intermediate shaft. This three-shaft (also called three-axis) design results in a very short axial length for better packaging. There are three separate shift fork shafts, which hold three shift forks to activate the synchronizer rings for the two gearsets on each of the three gear shafts. The shift forks are activated by a cable system. The clutch release bearing is operated by a concentric slave cylinder that surrounds the input shaft in the clutch housing. A concentric slave cylinder allows more linear clutch feel than an external lever-actuated clutch and release bearing. The input shaft carries the 3rd and 4th gear synchronizer, the intermediate shaft carries the 1st and 2nd gear synchronizer, and the output shaft carries the 5th and reverse gear synchronizer. The aluminum case contains a conventional final drive gearset.
There are sintered bronze double-cone blocker rings on the synchronizers for 1st and 2nd gears, while 3rd and 4th gears use carbon fiber blocker rings, and 5th and Reverse gears use molybdenum on their synchronizers. Carbon and molybdenum are extremely durable friction surfaces that remain stable even under extreme heat. Reverse gear is synchronized, which is a design advantage. That means the vehicle does not have to be completely stationary in order for reverse gear to be selected by the driver. On-going improvements include refinements such as a new synchronizer sleeve for first and second gear that improves cold-weather engagement of the gears.
Several refinements differentiate the applications of the F23: The concentric slave cylinder, which hydraulically actuates the clutch pressure plate, was redesigned to match the engine configuration in the Chevy Cobalt. VUE and ION use a reservoir where brake and clutch fluid share the same reservoir body, although partitions inside the reservoir keep the fluid for each function separate.