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Gearbox Disassembly
Refer to Figure 18.
1.
Remove top cover (22) from housing. Turn gearbox upside down and
pour out remaining gear oil from gearbox.
2.
Remove oil cap (20) (to be replaced).
3.
Remove snap ring (10) and shim (13) from input shaft (3).
4.
Support gearbox in hand press and push on input shaft (3) to remove
bearing (7).
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 snap ring (21), washer (8), and seal (18).
11.
Remove cotter pin (9), castle nut (14), and washer (17) from output shaft
(4).
12.
Remove output shaft (4) by using a punch and hammer 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 hammer 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 pattern 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
Refer to Figure 18.
NOTE: Repair to this gearbox is limited to replacing bearings, seals, and gas-
kets. Replacing gears, shafts, and a housing is not cost effective. Purchasing a
complete 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 diameter. 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 already 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 0.30 mm, insert shim between input shaft (3) and rear
MAN1261 (4/11/2018)
bearing (7). Repeat until end float is less than 0.30 mm. Check rotational
torque by hand. The torque should be less than .249 N-m.
16.
Check that the gear backlash is between 0.15 mm and 0.41 mm. You
should not have to adjust the backlash.
17.
Press in input oil seal (19), using tube of correct diameter. 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
.27 BAR compressed air and immerse the gearbox in water to verify that
there are no leaks.
20.
Remove gearbox from water and dry off with compressed 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 without mechanical assis-
tance.
1.
Set gearbox on gearbox stand and fasten with bolts and nuts. Torque
bolts to 237 N-m.
2.
Attach drive sheave to output shaft. Secure using castle nut and
hardware previously removed. Torque castle nut to 230 N-m.
3.
Attach gearbox stand to mower using four flanged 1/2" cap screws.
Drive Sheave Installation
Refer to Figure 21.
1.
When gear stand is installed on mower, the distance from the top of the
mower deck to the center line of the lower groove on the drive pulley
must be 66 mm (±.81 mm). This is a critical dimension and must be
carefully adjusted for proper belt life.
2.
Tighten gear stand hardware.
3.
Fill gearbox half full with SAE 90W gear lube.
4.
Check level after waiting five minutes to permit lube to work through
bearings. Add lube, if necessary, until gearbox is half full.
5.
Replace driveline shield. Attach driveline to gearbox.
Figure 21
. Drive Sheave Installation
UNIVERSAL JOINT REPAIR
1. Yoke
2. Cup and bearings
3. Snap ring
4. Journal cross
Figure 22
. U-Joint Exploded View
U-Joint Disassembly
1.
Remove external snap rings from yokes in four locations as shown in
Figure 23.
Dealer Service 19
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