Service Manual

7-9
WPM Drive Systems Manual
WHEELPINIONCLUTCH
SpringRatchetStyle
The Spring Ratchet type wheel clutch system has been
used on a wide variety of models. It consists of a spring
supporting a drive key which engages the pinion. When
the mower drive is engaged the axle turns the key which
is engaged with an internal tooth on the pinion. The
pinion turns the wheel gear. When the mower is pushed
or turned, the pinion must rotate faster than the axle.
As the pinion rotates it depresses the key, allowing the
differential action.
The axle drives both keys and pinions equally but they
will ratchet individually. When the mower is pulled
backwards, this type of clutch does not disengage. It will
require the axle and transmission to turn backwards. It is
critical to easy backing to make sure the self-propel belt
properly disengages.
ServicingtheSystem
The things that can impede the function are dirt, rust or
wear. The owner’s manual requires that ordinary engine
oil be added to each side of the pinion periodically.
This is to keep the anti seize from drying up. If that is
not done, it will be necessary to remove the pinion,
key and spring to clean and re-lubricate with anti-seize
compound.
On the left side there will be two keyed thrust washers
and one regular thrust washer. Clean the end of the axle,
keyway, and the parts removed. Inspect the key; if worn,
replace. Make sure the thrust washers have the key tab
on them. If the tab is broken, the pinion will tend to push
the retaining rings out of their grooves.
Lubricate the key, spring, and axle with anti-seize
compound and reassemble. Note the pinion has the
letter “R” stamped on one side and “L” on the other. If
you are on the right side of the mower, the letter “R”
should face you when you install the pinion. The letter
“L” should be visible on the left side of the mower.
WHEELPINIONSERVICE
The steps to service the wheel pinions are the same for
both front and rear wheel drive models.
1. Raise the mower until the wheel is off the ground.
Support with a block.
2. Remove the wheel bolt, wheel and wheel cover (Fig.
175).
Fig175 MVC-739
3. Remove the retaining ring and thrust washer (Fig.
176).
Fig176 MVC-746