Manual Transmission Construction and Servicing

Manual Transmission Construction











The manual transmission consists of the input shaft, main shaft, countershaft and reverse idle gear shaft which are installed in the die-cast aluminum alloy and cast-iron cases. This transmission provides five forward speeds and one reverse speed.

The 1st, 2nd and 3rd speeds are for speed reduction drive, 4th speed is for direct drive and 5th speed is for over drive.

The low speed (1st and 2nd) synchronizer is mounted on middle of the main shaft and engaged with the main shaft 1st or 2nd gear. The high speed (3rd and 4th) synchronizer is mounted on forefront of the main shaft and engaged with the main shaft 3rd gear or input shaft. The 5th speed synchronizer is mounted on the countershaft and engaged with the countershaft 5th gear. The 5th speed synchronizer is also equipped with the prevention device from gear cracking noise when shifting gear into the reverse gear. The triple cone synchronizer mechanism is provided to the 1st, 2nd and 3rd gear synchromesh devices for high performance of shifting into the 1st, 2nd and 3rd gear.

The gear shift lever case is located at the upper behind the transmission case and has a cam which prevents direct gear shifting from the 5th speed gear into the reverse gear. As the die-cast aluminum alloy and cast-iron cases are sealed with liquid type gasket, it is necessary to use genuine sealant or its equivalent on its mating surface when reassembling them. Also, the case fastening bolts must be tightened to specified torque by means of the torque wrench and tightening over or below the specified torque should be avoided.

The description under Repair Instructions covers the transfer partially which is next to the transmission as well, but their gear boxes are independent and each of them has its own drain and level/filler plugs for the oil change or the level check.