Briggs & Stratton MB (18 HP) Lawn Mower User Manual


 
Maintenance Instructions LUBRICATION
40
Mower Deck Gearbox Lubrication
The mower deck gearboxes (tee gearbox and blade
drive gearboxes) are connected as a unitized
assembly, and oil flows freely between them. The
gearboxes are permanently lubricated (oil filled) and
sealed requiring no scheduled lubrication. However,
the gearbox oil seals should be checked every 25
hours for indication of an oil leak; particularly the
lower seals on the blade drive gearboxes should be
inspected, since they operate in a dirty environment.
If an oil leak is noted, replace the oil seal and relu-
bricate the gearbox assembly as follows:
1. Remove gearbox cover (footrest). Deck orien-
tation should be the normal operating position.
Mower Deck Gearboxes
(shown with gearbox cover removed for clarity)
2. Clean the area around the individual gearbox
cover plates to prevent contaminants from
entering the gearcase.
3. Remove the screws securing the cover plates
on the blade drive gearboxes.
4. Check the level of lubricant in the gearboxes. If
the lubricant is low, add SAE E.P. (Extreme
Pressure) 90W oil until the oil level is up to (sub-
merges) the horizontal shaft in the gearbox
(shaft parallel to cover plate).
NOTE: In case the gearboxes are completely
drained of oil, approximately 5 fl. oz. (15 cl) of oil
per gearbox is required to refill the gear drive
assembly.
NOTE: Since the gearboxes are connected as
a unit by connector tubes, it is necessary to add
oil slowly. Allow a few minutes after adding oil
for the oil to flow throughout the assembly and
the oil level to stabilize before reassembly.
IMPORTANT: DO NOT overfill the deck gear-
boxes. The gearbox assembly is not vented,
and overfilling with oil will cause excessive pres-
sure and result in oil leaks.
5. Check condition of the cover gasket and replace
if worn or damaged. Reinstall gearbox cover
plates; torque screws to 24 in-lb (2.7 N
·m).
Transaxle Lubrication
The transaxle oil lubrication is SAE 20W-50 (API
Service Class SL or higher) engine oil.
Inspect both transaxle cases and hoses after ev-
ery 100 hours of operation for visible leaks.
The fluid levels for each transaxle can be
checked visually by looking at the fluid levels in each
expansion reservoir. When the transaxles are cold,
the fluid level in the expansion reservoirs should be
between 1/4" and 1/2" (.64 cm and 1.27 cm).
Expansion Reservoir Location
Transaxle Oil and Filter Change
Change the transaxle oil after the initial break-in
period of 50 hours. Thereafter, change oil every
250 hours of operation as follows:
1. Thoroughly clean the exterior of the transmis-
sion housing before servicing. Using a 1/4” hex
wrench, remove the plug on the underside of
each transaxle allowing the oil to drain.
2. Remove and replace the oil filters using a 3/8”
hex wrench. (Refer to Transaxle Oil Filter
Location photo.)
Blade Drive
Gearboxes
Tee
Gearbox
Reservoir Cap
Hot Level
Cold Level