Troubleshooting Tips - 3 Speed Transmission; Hard Shifting; Slipping Gears - Toro 20330 - Low Wheel Walk Power Mower Service Manual

THREE SPEED TRANSMISSION
TROUBLESHOOTING TIPS - 3 SPEED
TRANSMISSION

Hard Shifting

A raised boss molded into each gear causes the leading
edge of the key to depress before it can enter the next
gear (Fig. 132).
The ring on the shift collar end of the key holds the drive
end of the key up. If dried grease or dirt keeps the keys
from rocking up and down, the force required to shift
gears will increase. Check the cable for free movement
where it enters the transmission. These are quick checks
and should be made before opening the transmission.

Slipping Gears

The actual gears are in constant mesh. Unless gear
teeth are broken off, they cannot slip. If the wheels lurch
forward, then pause and lurch again, along with a loud
bang each time, the keys might be slipping.
4-12
Fig 132 3428-0067
Look at the key and the notch in the gear that it engages.
Excessive wear to the tip of the key or the notch in the
gear may be the problem (Fig. 133).
A
A. Shift collar
If the forces push straight on the key, it will drive the
axle. However, if due to wear the force tries to depress
the key, it can lower enough to disengage from the notch
in the gear (Fig. 134).
A
A
A. Gear
B. Key
B
Fig 133 3428-0065
B. Shift keys
C
B
D
B
Fig 134 gear and key
C. Good gear and key
D. Worn gear and key
WPM Drive Systems Manual