The transmissions all have an attached nameplate for identification. Refer to Transmission Identification in General Information for transmission data plate location and model number identification information.

Manual transmissions receive power (torque) from the engine to the transmission input shaft. The spines of the input shaft engage internal splines in the hub of the main drive gear. Torque is split off between two countershaft drive gears. The torque is then delivered along both countershaft gears to the mating countershaft gears.

The internal clutching teeth mainshaft gear hub transfers torque to the mainshaft via the sliding clutch. The mainshaft transfers torque to the auxiliary drive gear. The auxiliary countershaft drive gear splits between the two auxiliary countershaft drive gears and supplies torque to the output shaft through reduction gears, low range gears, or sliding clutches (depending on the type of transmission).

A clutch assembly is used to disengage and engage the transmission/engine driveline. This allows the driver to select the proper transmission gear ratio in order to match the vehicle load and speed. The driver uses the transmission shift control lever in order to select the gear ratio. The vehicle starts in low or the first speed gear.

Some vehicles may have an auxiliary transmission or a two speed rear axle. The auxiliary transmission, if used, is mounted behind the main transmission and used to increase gear ratio selection. The two-speed rear axle is also used to increase gear ratio selection.