24
Dealer Service
MAN1289 (10/18/2019)
3.
Remove cotter pin or wire, washer, and nut from
vertical shaft and remove crossbar (see
Crossbar
Removal, page 37
).
4.
Remove the four bolts that attach gearbox to cutter
and remove gearbox.
Disassemble Gearbox
1.
Remove plug from side of gearbox and pour out
remaining gear oil.
2.
Support housing in vise in a vertical position.
3.
Remove input seal (4) (to be replaced).
4.
Remove retaining rings (6) and (8).
5.
Remove the six cap screws (24), washers (23) and
top cover (2) from housing.
6.
Remove retaining ring (6) behind gear (3).
7.
Support gearbox in hand press and pull input shaft
(5) through gear (3). Remove ball bearing (21).
8.
Remove ball bearing (20) and gear spacer (7) from
input shaft (5).
9.
Support housing in vise in a horizontal position.
10.
With the hub/stump jumper/crossbar, castle nut,
cotter pin, wire and washer already removed,
remove the four cap screws (13), lock washers (12)
and output cap (17).
11.
Remove output gaskets (11) and (10).
12.
Push output shaft and pinion (19) down and
remove ball bearing (20) or tapered roller bearings
(25), output bearing spacer (18), and retaining ring
(6). Remove output shaft and pinion (19).
NOTE:
On gearboxes with tapered roller bearings,
it will be necessary to use a punch to drive out
bearing cups.
13.
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.
14.
Inspect vertical and horizontal shafts for grooves,
nicks, or bumps in the areas where the seals seat.
Resurface any damage with emery cloth.
15.
Inspect housing and caps for cracks or other
damage.
SEAL REPAIR - BB48.30, BB60.30, BB72.30
(Figure 17)
Vertical Shaft Seal Repair
1.
Disconnect and remove the rear driveline from the
gearbox.
2.
Remove vent plug (9) and siphon gear lube from
housing through this opening.
3.
Remove crossbar (see
Crossbar Removal, page
36
).
4.
Remove output cap (17) and output seal (16) by
removing four cap screws (13) and washers (12).
Replace with new seal (see
Seal Installation,
page 23
).
Vertical seal should be recessed in output cap.
NOTE:
Distortion to seal cage or damage to seal
lip will cause seal to leak.
5.
Secure output cap (17) on to bottom of gearbox
using four cap screws (13) and lock washers (12).
NOTE:
Make sure output gasket (10) and (11) are
in place.
6.
Fill gearbox with SAE 80W or 90W gear lube until it
runs out the side level plug.
7.
Remove and replace any seal damaged in
installation.
Horizontal Seal Leak Repair
1.
Disconnect and remove the rear driveline from the
gearbox.
2.
Remove vent plug (9) and siphon gear lube from
housing through this opening.
3.
Remove input seal (4). Replace with new one
(refer to
Seal Installation, page 23
).
Fill gearbox with SAE 80W or 90W gear lube until it
runs out the side level plug.
Reassemble Gearbox - BB48.30, BB60.30,
BB72.30
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 upper output bearing cups (25) in the
housing and press using a round tube with the
correct diameter.
4.
Slide shims (26) over output shaft (16). Use the
same thickness as removed as a starting point.
5.
Push bearing cone (25) onto output shaft (16).
Shims maybe required between cone (25) and
retaining ring (6) to eliminate any space.
NOTE:
Make sure there is no endplay or gaps in
this assembly.
6.
Insert output bearing spacer (18) and bearing cone
(25) over output shaft until seats against upper
bearing (25). Press lower bearing cup into position
as shown.
7.
Secure output cap (17) with new output seal (16)
installed to bottom of gearbox housing using the
four 10mm x 1.5 x 25 cap screws (13) and lock
washers (12). Use shim gaskets (10) and (11) to
