Toro Workman 3000 Series, Service Manual

Page: 271 / 306

Front Wheel
Drive (4WD)
When a change in backlash is required, backlash shims
should be changed in the range of 1-1/2 times the
RING GEAR
RING GEAR
DRIVE SIDE
COAST SIDE
amount of backlash required to bring the gears into
specification. For example, if the backlash needed to be
changed by .004”, the shim pack should be changed by
.006” as a starting point.
High backlash is corrected by moving the ring gear clos-
er to the pinion. Low backlash is corrected by moving the
ring gear away from the pinion. These corrections are
made by switching shims from one side of the differential
case to the other.
Figure 54
Heel Heel
Toe Toe
Example 1: Backlash correct. Thicker pinion position
RING GEAR
RING GEAR
shims required (Fig. 54).
DRIVE SIDE
COAST SIDE
Heel Heel
Example 2: Backlash correct. Thinner pinion position
shims required (Fig. 55).
Example 3: Backlash incorrect. Thinner pinion position
shim required. Adjust backlash to match (Fig. 56).
GEAR PATTERN MOVEMENT SUMMARY:
Toe Toe
1. Decreasing backlash moves the ring gear closer to
Figure 55
the pinion.
RING GEAR
RING GEAR
A. Drive pattern (convex side of gear) moves lower
DRIVE SIDE
COAST SIDE
and toward the toe.
Heel Heel
B. Coast pattern (concave side of gear) moves
slightly higher and toward the heel.
2. Increasing backlash moves the ring gear away from
the pinion.
Toe Toe
A. Drive pattern (convex side of gear) moves higher
and toward the heel.
Figure 56
B. Coast pattern (concave side of gear) moves
slightly lower and toward the toe.
3. Thicker pinion position shim with the backlash
constant moves the pinion closer to the ring gear.
A. Drive pattern (convex side of gear) moves deeper
on the tooth (flank contact) and slightly toward the
toe.
B. Coast pattern (concave side of gear) moves
deeper on the tooth and toward the heel.
4. Thinner pinion position shim with backlash constant
moves the pinion further from the ring gear.
A. Drive pattern (convex side of gear) moves toward
the top of the tooth (face contact) and toward the
heel.
B. Coast pattern (concave side of gear) moves to -
ward the top of the tooth (face contact) and toward
the heel.
Workman 4000 Series Page 10 – 29 Front Wheel Drive (4WD)