A practical closed-type test rig is here described for testing the tractor gear transmission, A new arrangement was developed to improve the structure of the loading gear box with odd number gears.

Waterproof: for PEVA rubber material closed type air bubble structure, each of the gas chamber in close condition.

Theaction of the Closed system, the phenomena of the split flow of power and the force in the closed type of differential gear train have been demonstrated.