30 Dealer Service
MAN1331
(09/29/22)
Figure 19.
Gearbox Stand Assembly
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 oth-
er 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 shaft gasket or seal can be
repaired without removing the gearbox from the mower.
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.
Figure 20.
Seal Installation
2
3
4
CD1094
1
CD1092
1. Seal
2. Pipe or tube
3. Seal seat
4. Casting
Pipe or tube must
press at outer
edge of seal
Incorrect
Installation
13
17
CD9274 AB
21
37
19
36
16
8
8 Sheave, 12.65 PD X 1.25, B
13 Shield, Clutch
16 Nut, HFN 5/8 NC Lock
17 Bolt, HEX Flange M8 X 16 GR 8.8 DRI-LOC
19 Sleeve 1.25 X 1.75 X .75
21 Bolt, CRG 5/8 X 1-3/4 GR 5 ZP
36 Pin, Cotter 1/8 X 2”
37 Nut, Castle M24 X 2
