HOW A TOPLOADER WORKS

In first-speed, the first & second-speed synchronizer sleeve is moved rearward by the shift fork. The sleeve engages the first-speed blocking ring, which acts as a cone clutch applied to the free-wheeling first-speed gear. This action speeds up or slows down the first-speed gear to match the speed of the output shaft. Further movement of the sleeve locks the first & second speed synchronizer hub to the first-speed gear by means of internal splines.

On engagement of the clutch, power flows through the input shaft & gear to the meshed countergear and then to the first-speed gear. This gear transmits the power through the locked synchronizer hub to the output shaft. All other forward-speed gears are in idler motion, as they are driven by the counter gear, but they do not transmit power because they are not locked to the output shaft. All other forward-speed shifts are made in the same manner as the first-speed shift due to the constant mesh feature. The shift to the fourth-speed gear locks the third & fourth-speed synchronizer sleeve to the input shaft. This allows power to flow straight through the input and output shafts.