POWER TRAIN GRT880 SERVICE MANUAL
7-28
Published 10/19/2017, Control # 618-00
Servicing the Crane after Transmission/torque
Converter Overhaul
The transmission/torque converter and its allied hydraulic
system are important links in the drive line between the
engine and the wheels. The proper operation of either the
unit or the system depends greatly on the condition and
operation of the other; therefore, whenever repair or
overhaul of the transmission/torque converter is performed,
the balance of the system must be considered before the job
can be considered completed.
After the overhauled or repaired transmission/torque
converter has been installed in the crane, the oil cooler and
connecting hydraulic system must be thoroughly cleaned.
This can be accomplished in several ways, and a degree of
good judgement must be exercised as to the method
employed.
The following are considered the minimum steps to be taken:
1. Drain the entire system thoroughly.
2. Disconnect and clean all hydraulic lines. Where feasible,
hydraulic lines should be removed from the machine for
cleaning.
3. Replace oil filter elements, cleaning out the filter cases
thoroughly.
4. The oil cooler must be thoroughly cleaned. The cooler
should be back flushed with oil and compressed air until
all foreign material has been removed. Flushing in the
direction of normal oil flow will not adequately clean the
cooler. If necessary, the cooler assembly should be
removed for cleaning, using oil, compressed air and a
steam cleaner for that purpose.
5. Remove the drain plug from the transmission/torque
converter and inspect the interior of the unit housing,
gears, etc. If the presence of considerable foreign
material is noted, it will be necessary for the unit to be
removed, disassembled, and cleaned thoroughly. It is
realized this entails extra labor, however, such labor is a
minor cost compared to the cost of difficulties which can
result from the presence of such foreign material in the
system.
6. Assemble all components and use only the type oil
recommended. Fill the transmission through the fill pipe
until fluid is at the top of the fill range on the dipstick. Run
the engine for two minutes at idle (1200 rpm) to prime
the torque converter and hydraulic lines. Recheck the
level of oil in the transmission with the engine running at
idle (1200 rpm). Add oil as necessary to bring the level
to the LOW mark on the dipstick. After the oil
temperature reaches 82°C to 93°C (180°F to 200°F),
add oil to bring the level to the FULL mark on the
dipstick.
7. Recheck all drain plugs, lines, connections, etc., for
leaks and tighten where necessary.
Lubrication
Type of Oil and Capacities
Refer to Maintenance and Lubrication, page 9-1 for types of
oil and capacities.
Normal Drain Period
NOTE: Normal drain periods and filter change intervals are
for average environmental and duty-cycle
conditions. Severe or sustained high operating
temperatures or very dusty atmospheric conditions
will cause accelerated deterioration and contam-
ination. For extreme conditions, judgment must be
used to determine the required change intervals.
NOTE: It is recommended that filter elements be changed
after 50 and 100 hours of operation on new and
rebuilt or repaired units, then at normal intervals
thereafter. Refer to Maintenance and Lubrication,
page 9-1.
a. Drain transmission and remove pump screen. Clean
screen thoroughly and replace, using a new gasket.
b. Remove and discard oil filter. Clean filter housing
and install new filter.
c. Refill transmission to LOW mark.
d. Run engine at 1200 rpm to prime converter and
lines.
e. Recheck level with engine running at 1200 rpm and
add oil to bring level to LOW mark. When oil
temperature is hot [82°C to 93°C (180°F to 200°F)],
make final oil level check. Bring oil level to full mark.
Towing or Pushing
Before towing crane, disconnect both front and rear drive
lines. Engine can not be started by pushing or towing
because of hydraulic system design.
CAUTION
Do not use flushing compounds for cleaning purposes.
Reference Only
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