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.
To see individual parts and
their locations, refer to the Exploded View page.