Power transmission system

A power transmission system for transmitting a driving force of a prime mover to driving wheels via a stepped transmission,

• said stepped transmission comprising:
• an input shaft connected to the prime mover;
• an output shaft connected to the driving wheels;
• a first gear pair for an L-th speed position, a second gear pair for an M-th speed position higher than the L-th speed position, and a third gear pair for a speed position other than and higher than the L-th speed position and the M-th speed position, each of said gear pairs having an input gear arranged on said input shaft, and an output gear arranged on said output shaft and in mesh with said input gear, with one gear of said input gear and said output gear being rotatably supported on said input shaft or said output shaft;
• first to third synchromeshes for transmitting the driving force of the prime mover from said input shaft to said output shaft via said gear pairs;
• and
• synchromesh control means for controlling respective operations of said first to third synchromeshes,
• wherein when a speed position of said transmission is shifted from the L-th speed position to the M-th speed position, said synchromesh control means causes said third synchromesh to move toward said third gear pair by a first predetermined amount which is not large enough to bring said third synchromesh into meshing engagement with said third gear pair, to transmit the driving force of the input shaft to the output shaft via said third gear pair.