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► The manual transmission allows a driver to manually vary engine torque and output to the drive train.

► The ability of the technician to drive, service, repair, and maintain the manual transmission/transaxle is a critical skill.

► A manual transmission/transaxle allows the driver to directly vary the gear ratio by manual selection, between the engine and the driving road wheels.

► The components of a manual transmission can vary depending on the use and size of the transmission.

► The gear ratio is the number of turns of the input gear, necessary to achieve one turn of the output gear.

► Gear ratio theory will help you to understand how power is distributed and how power and speed varies as the vehicle travels.

► In keeping with the gear ratio theory, compound gear trains have two or more pairs of gears in constant mesh, so that they rotate together and are found inside the transmission/transaxle.

► In direct drive rotation, both the output and input gears turn at the same speed, and the turning effort of the output gear will equal the effort applied by the input gear.

► All gear boxes have shift rails and shift forks. The gear shift lever/mechanism can be located on the top, on the side or on the column.

► The interlock mechanism is the device that ensures two gears cannot be selected at the same time.

► Many newer manual transmissions are equipped with Electronic Reverse Lockout systems, which use an electronic solenoid to prevent the transmission/transaxle from being shifted into reverse while the vehicle is in forward motion.

► In a manual transmission/transaxle, the gears and shafts are supported on bearings or bearing surfaces to reduce rolling friction.

► Roller bearings are used to support radial loads.

► Caged roller bearings can be used to support gear rotating on an output shaft.

► Thrust washers act as wear surfaces and can be used to adjust end-play.

► Tapered roller bearings are used to sustain radial and thrust loads.

► Transmission problems include nose, hard shifting, jumping out of gear, no gear selection, and fluid leaks.

► Lubrication type and condition are critical factors in transmission performance and reliability.

► Having the gearbox and final drive gears in one casing provides a compact and relatively quiet unit and fits well into front wheel drive vehicles.

► Historically, manual transmissions have not required the use of electronics, but as with all vehicle systems, electronics are starting to play a more common role.

► Manual transaxles problems can be diagnosed with the guidance of the manufacturer’s diagnostic tables.

► A simple issue that can cause hard shifting is created by maintenance work that is performed improperly on a manual transmission/transaxle.

► Always adjust shift linkage following the manufacturer’s methods.

► Always refer to the manufacturer’s prescribed maintenance schedules and fluid changes to ensure the unit lasts the life of the vehicle.