32 Dealer Service
MAN1331
(09/29/22)
4.
Support gearbox in hand press and push on input
shaft (3) to remove bearing (7) and spacer (11).
5.
Remove gear (1) from inside housing.
6.
Remove oil seal (19) from front of housing (to be
replaced).
7.
Remove snap ring (10) and shim (13) from front of
housing (2).
8.
Remove input bearing (7) by using a punch and
hammer from outside of housing.
9.
Support housing in vise in a horizontal position.
10.
The castle nut (15) and cotter pin (25) are already
removed with the drive sheave. Remove the snap
ring (21), washer (8), and seal (18).
11.
Remove cotter pin (9), castle nut (14), and washer
(8) from output shaft (4).
12.
Remove output shaft (4) by using a punch and ham-
mer and tap on top to drive down.
13.
Remove gear (5) and shim (16) from inside housing.
14.
Remove bearing (26) by using a punch and hammer
from the top, outside the housing.
15.
Support housing upside down (top cover surface)
and remove bearing (6) by using a punch and ham-
mer from the bottom side of the housing.
16.
Inspect gears for broken teeth and wear. Some wear
is normal and will show on loaded side. Forged gear
surfaces are rough when new. Check that wear pat-
tern is smooth.
17.
Inspect vertical and horizontal shafts for grooves,
nicks, or bumps in the areas where the seals seat.
Resurface any damage with emery cloth.
18.
Inspect housing and caps for cracks or other
damage.
Gearbox Reassembly
(Figure 21)
NOTE:
Repair to this gearbox is limited to replacing
bearings, seals, and gaskets. Replacing gears, shafts,
and a housing is not cost effective. Purchasing a com-
plete gearbox is more economical.
1.
Clean housing, paying specific attention to areas
where gaskets will be installed.
2.
Wash housing and all components thoroughly.
Select a clean area for gearbox assembly. Replace
all seals, bearings, and gaskets. All parts must be
clean and lightly oiled before reassembling.
3.
Insert output bearings (6 & 26) in the housing, using
a round tube of the correct diameter and a hand
press.
4.
Slide output shaft (4) through both bearings (6 &
26) until it rests against bearing (6).
5.
Slide shim (16) over output shaft (4).
6.
Press gear (5) onto output shaft (4) and secure with
washer (17), castle nut (14), and cotter pin (9).
7.
Apply grease to lower seal lips (18) and press seal
over output shaft (4), using a tube of the correct di-
ameter. Be sure not to damage the seal lip. Press in
housing so that seal is recessed.
8.
Insert protective washer (8) by hand. Install snap
ring (21) and position it together with dual lip seal
(18) by pressing it into position. Verify that snap ring
is seated correctly.
9.
Press bearing (7) into the housing, using a round
tube of the correct diameter and a hand press.
Secure with shim (13) and snap ring (10).
10.
Secure snap ring (11) on input shaft (3) if not al-
ready secure.
11.
Place gear (1) through top of housing and align gear
(1) and gear (5) so that gear teeth are a match.
12.
While holding gear (1) in place, slide input shaft (3)
through gear (1) and bearing (7). Align splines on
shaft (3) and gear (1).
13.
Slide spacer (12) over input shaft (3) and press
bearing onto input shaft (3), using a round tube of
the correct diameter and a hand press.
14.
Slide shim (13) over input shaft (3) and secure with
snap ring (10).
15.
Check input shaft end float by moving the input
shaft (3) by hand. If end float is higher than 0.012",
insert shim between input shaft (3) and rear bearing
(7). Repeat until end float is less than 0.012". Check
rotational torque by hand. The torque should be less
than 2.2 lbs-inch.
16.
Check that the gear backlash is between 0.006" and
0.016". You should not have to adjust the backlash.
17.
Press in input oil seal (19), using tube of correct di-
ameter. Be careful not to damage seal lip.
18.
Press oil cap (20) on to cover the rear of housing,
using a tube of the correct diameter.
19.
Check gearbox housing for leaks by plugging all
holes except one. Apply 4 psi compressed air and
immerse the gearbox in water to verify that there
are no leaks.
20.
Remove gearbox from water and dry off with com-
pressed air. Add SAE 80W or 90W EP oil until it runs
out of side level hole. Tighten all plugs.
Gearbox Installation
NOTE:
Gearbox is heavy: do not attempt to move with-
out mechanical assistance.
1.
Set gearbox on gearbox stand and fasten with bolts
and nuts. Torque bolts to 175 lbs-ft.
2.
Attach drive sheave to output shaft. Secure using
castle nut and hardware previously removed.
3.
Attach gearbox stand to mower using four hex
screws.
