Ring To Pinion Gear Engagement (Front Axle) - Toro Groundsmaster 3280-D Service Manual

Ring to Pinion Gear Engagement (Front Axle)

Final position of front axle pinion is verified by using the
gear contact pattern method as described in the follow-
ing procedure.
GEAR TOOTH DEFINITIONS (Fig. 55):
Toe - the portion of the tooth surface at the end to-
wards the center.
Heel - the portion of the gear tooth at the outer end.
Top Land - top surface of tooth.
1. Paint the teeth of the ring gear, both drive and coast
side, with a gear marking compound, such as DyKemR
Steel Blue.
2. While applying a light load to the ring gear, rotate the
pinion gear until the ring gear has made one complete
revolution. The drive side pattern should be located at
the toe portion of the tooth. The coast pattern should
also be at the toe portion of the tooth (Fig. 56).
Study the patterns in the following illustrations and cor-
rect engagement as necessary.
NOTE: When making changes, note that two variables
are involved. Example: If you have the backlash set cor-
rectly to specifications and you change the pinion posi-
tion shim, you may have to readjust backlash to the
correct specification before checking the pattern.
Every gear has a characteristic pattern. The illustrations
show typical patterns only and explain how patterns shift
as gear location is changed. When making pinion posi-
tion changes, shims should be changed in the range of
.002 to .004 in. (.05 to .10 mm) until a correct pattern has
been obtained.
When a change in backlash is required, backlash shims
should be changed in the range of 1-1/2 times the
amount of backlash required to bring the gears into
specification. For example, if the backlash needed to be
changed by .004 in. (.10 mm), the shim pack should be
changed by .006 in. (.15 mm) 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.
Example 1: Backlash correct. Thicker pinion position
shims required (Fig. 57).
Example 2: Backlash correct. Thinner pinion position
shims required (Fig. 58).
Groundsmaster 3280−D/3320
TOP LAND
ROOT
DRIVE SIDE
Heel
DRIVE SIDE
Heel
DRIVE SIDE
Heel
Page 8 − 29
PROFILE
TOE
LENGTHWISE
BEARING
ARC
HEEL
Figure 55
COAST SIDE
Toe Toe
Figure 56
COAST SIDE
Toe Toe
Figure 57
COAST SIDE
Toe Toe
Figure 58
Drive Axles
Heel
Heel
Heel