The gear train (Manual gearbox - R380)

The gear train

The gear train comprises an input shaft, output shaft, layshaft and reverse idler shaft together with their appropriate gears and synchromesh assemblies.

The gear train input shaft, output shaft and layshaft are supported by taper roller bearings with all gears on the input and output shafts running on caged needle roller bearings. Layshaft gears are integral with the shaft with the exception of reverse/5th gears which are splined to the shaft and retained with a nut. 1st, 2nd, 3rd and 4th gears are shot peened to improve durability. The reverse idler shaft and gear are supported in the centre plate by a caged needle roller bearing. End-float of the output shaft and layshaft is controlled by selective shims located in the centre plate whilst reverse idler shaft end-float is controlled by a selective shim located behind reverse gear.

Operation

Drive is transmitted from the crankshaft, through the clutch to the gearbox input shaft which transmits drive via the layshaft to the output shaft in all gears with the exception of 4th gear which provides a direct drive from the input shaft to the output shaft. Drive from the gearbox output shaft is transmitted to the transfer box input shaft via a flange splined to the output shaft.