IIn a manual transmission for a rear-wheel drive vehicle, the gear train is built up on three shafts: the input shaft, the countershaft, and the main shaft.
In transaxle designs, the drive is transferred through the clutch unit to a primary shaft. The primary shaft carries gears of different sizes which mesh with gears on a secondary shaft.
In transaxle designs, the synchromesh unit is located between the end of each engagement sleeve and the gear. The engagement hubs and sleeves may be located on the primary or on the secondary shaft, depending on design.
