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Dealer Service 29
5WPMAN0183 (Rev. 4/25/2008)
GEARBOX REPAIR
Read this entire section before starting any repair.
Many steps are dependent on each other.
Fill gearbox with SAE 80W or 90W gear lube until it
runs out the side level plug.
Repair to this gearbox is limited to replacing bearings,
seals, and gaskets. Replacing gears, shafts, and a
housing is not cost effective. It is more economical to
purchase a complete gearbox if repair to anything other
than replacement of bearings, seals or gaskets is
required.
Inspect gearbox for leakage and bad bearings.
Leakage is a very serious problem and must be cor-
rected immediately.
Bearing failure is indicated by excessive noise and
side-to-side or end play in gear shafts.
Seal Replacement
Recommended sealant for gearbox repair is Permatex
Aviation 3D Form-A-Gasket or equivalent.
Leakage can occur at the vertical or horizontal gaskets
and shaft seals.
Leakage at the horizontal gasket or seal can be
repaired without removing the gearbox from the cutter.
Seal Installation
Figure 18. Seal Installation
NOTE: Proper seal installation is important. An improp-
erly installed seal will leak.
1. Clean area in housing where seal outer diameter
(OD) seats. Apply a thin coat of Permatex.
2. Inspect area of shaft where seal seats. Remove
any burrs or nicks with an emery cloth.
3. Lubricate gear shaft and seal lips.
4. Place seal squarely on housing, spring-loaded lip
toward housing. Select a piece of pipe or tubing
with an OD that will sit on the outside edge of the
seal but will clear the housing. Tubing with an OD
that is too small will bow seal cage and ruin seal.
5. Carefully press seal into housing, avoiding distor-
tion to the metal seal cage.
Vertical Shaft Repair (Figure 20)
1. Disconnect and remove the driveline from the
gearbox.
2. Remove vent plug (24) and siphon gear lube from
housing through this opening.
3. Remove gearbox stand from mower deck.
4. Remove gearbox and pulley from gearbox stand.
5. Remove vertical shaft seal (18). Replace with new
seal (see Seal Replacement, page 29).
Vertical seal should be recessed in housing. Horizontal
seal should be pressed flush with outside of housing.
NOTE: Distortion to seal cage or damage to seal lip will
cause seal to leak.
6. Fill gearbox with SAE 80W or 90W gear lube until it
runs out the level plug.
7. Assemble gearbox and pulley to gearbox stand.
Attach gearbox stand to mower deck.
Horizontal Leak Repair (Figure 20)
1. Disconnect and remove the driveline from the
gearbox.
2. Remove vent plug (24) and siphon gear lube from
housing through this opening.
3. If the leak occurred at either end of horizontal shaft,
remove oil cap (20) and/or oil seal (19). Replace
with new one (refer to Seal Replacement, page
29).
4. Fill gearbox with SAE 80W or 90W gear lube until it
runs out the level plug.
1. Seal
2. Pipe or tube
3. Seal seat
4. Casting
Pipe or tube must
press at outer
edge of seal
Incorrect
Installation