Yanmar 1GM User Manual page 227

TRANSMISSION-KBW SERIES
9. Refer to Steps 7 and 8 and disassemble the clutch com-
ponents on the reverse gear.
10. Lay the shift ring and pressure plate assembly flat.
11. Remove the pressure plate return springs (24, Figure
3), then lift off the top pressure plate (17) and remove the
steel balls (18).
12. Lift the shift ring (25, Figure 3) and driving plate (22)
off the bottom pressure plate and remove the three re-
maining balls.
13. Slip the shift ring (25, Figure 3) off the driving plate
(22).
14. Remove the alignment pins (21, Figure 3) and detent
pins (20) with springs (19) from the driving plate (22).
Inspection
I. Check the gear teeth for excessive wear, corrosion or
rust and mechanical damage. Check the teeth for galling,
chips, cracks, missing pieces, distortion or discoloration
from overheating. Check the splines for excessive wear or
damage. Replace the gears if damaged.
221
2. Inspect the output shaft bearings and seal surfaces for
excessive wear, grooving, metal transfer and discolor-
ation from overheating.
3. Inspect the key and output shaft keyway for damage.
NOTE
Shims behind the outer bearing race in the
mountingflange determine bearing preload
for the output shaft bearings. Save the shims
and reinstall them
if
reusing the original
parts.
4. Inspect the input shaft bearing outer races in the trans-
mission case and mounting flange. If either race is dam-
aged or excessively worn, remove it using a suitable
puller.
5. Measure steel plate warpage as shown in Figure 7 and
compare the result with the specification in
Table
3.
6. Measure the width of the steel plates tangs and com-
pare the result with the specification in
Table
3.
7. Measure the width ofthe grooves in the pressure plates
and compare the result with the specification in
Table
3.
The clearance between the tangs and the grooves should
be 0-0.6 rom (0-0.024 in.).
8.
Measure the width of the friction plates and compare
with the specification in
Table
3. Both sides of friction
plates have a 0.35 mm (0.014 in.) copper sintered layer.
Replace the friction plates when the copper layer is worn
more than 0.2 rom (0.008 in.) on one side.
9. Measure four friction plates. The sum of wear of four
friction plates (forward or reverse) must not exceed 0.8
mm (0.031 in.). If wear exceeds 0.8 rom (0.031 in.), re-
place all friction plates (forward or reverse).
10. Assemble each set of steel and friction plates. Com-
press the plates to remove steel plate warp. Measure the
assembled plates. The assembled thickness must exceed
10.0 mm (0.394 in.).
11. Measure the backlash between the teeth on the fric-
tion plates and the gear splines. The backlash must not ex-
ceed 0.9 mm (0.035 in.).
12. Lay the shift ring and pressure plate assembly flat and
remove the pressure plate return springs (24, Figure 3).
Lift off the top pressure plate (17) and remove the steel
balls (18).
13. Lift the shift ring (25, Figure 3) and driving plate (22)
off the bottom pressure plate and remove the three re-
maining steel balls. Slip the shift ring (25) off the driving
plate (22), remove the alignment pins (21) and detent pins
(20) with the springs (19) from the driving plate (22).
14. Inspect the pressure plate (17 and 23, Figure 3) ball
grooves for wear and renew the plate ifwear is noticeable.
15. Measure the pressure plate thickness and compare the
result with the specification in
Table 3.