POWER TRAIN RT540E SERVICE MANUAL
7-22 Published 4-20-2015, Control # 502-01
reaction member is the means by which the hydraulic torque
converter multiplies torque.
The reaction member of the torque converter is located
between and at the center of the inner diameters of the
impeller and turbine elements. Its function is to take the fluid
which is exhausting from the inner portion of the turbine and
change its direction to allow correct entry for recirculation
into the impeller element.
The torque converter will multiply engine torque to its
designed maximum multiplication ratio when the output shaft
is at zero rpm. Therefore, as the output shaft is decreasing in
speed, the torque multiplication is increasing.
The shift control valve assembly consists of a valve body
with selector valve spools. A detent ball and spring in the
selector spool provides one position for each speed range. A
detent ball and spring in the direction spool provides three
positions, one each for forward, neutral, and reverse.
With the engine running and the directional control lever in
the neutral position, oil pressure from the regulating valve is
blocked at the control valve, and the transmission is in
neutral. Movement of the forward and reverse spool will
direct oil, under pressure, to either the forward or reverse
direction clutch, as desired. When either directional clutch is
selected, the opposite clutch is relieved of pressure and
vents back through the direction selector spool. The same
procedure is used in the speed selector.
The direction or speed clutch assembly consists of a drum
with internal splines and a bore to receive a hydraulically
actuated piston. The piston is oil tight by the use of sealing
rings. A steel disc with external splines is inserted into the
drum and rests against the piston. Next, a friction disc with
splines at the inner diameter is inserted. Discs are alternated
until the required total is achieved. A heavy back-up plate is
then inserted and secured with a snap ring. A hub with OD
splines is inserted into the splines of discs with teeth on the
inner diameter. The discs and hub are free to increase in
speed or rotate in the opposite direction as long as no
pressure is present in that specific clutch.
To engage the clutch, the control valve is placed in the
desired position. This allows oil under pressure to flow from
the control valve, through a tube, to a chosen clutch shaft.
This shaft has a drilled passageway for oil under pressure to
enter the shaft. Oil pressure sealing rings are located on the
clutch shaft. These rings direct oil under pressure to the
desired clutch. Pressure of the oil forces the piston and discs
against the heavy back-up plate. The discs, with teeth on the
outer diameter, clamping against discs with teeth on the
inner diameter, enables the hub and clutch shaft to be locked
together and allows them to drive as a unit.
There are bleed balls in the clutch piston which allow quick
escape for oil when the pressure to the piston is released.
Maintenance
General Information
1. Always check the oil level with the engine idling, and the
transmission in neutral and at normal operating
temperature (82 to 93 °C [180 to 200 °F]).
2. Change the oil filter element every 500 hours. Drain and
refill the system every 1000 hours or 6 months.
Troubleshooting
The following data is presented as an aid to locating the
source of difficulty in a malfunctioning unit. It is necessary to
consider the torque converter charging pump, transmission,
oil cooler, and connecting lines as a complete system when
checking for the source of trouble, since the proper operation
of any unit therein depends greatly on the condition and
operation of the others. By studying the principles of
operation together with the data in this section, it may be
possible to correct any malfunction which may occur in the
system. Troubleshooting procedures basically consist of
hydraulic checks.
Hydraulic Checks
Before checking the transmission/torque converter and
associated hydraulic system for pressures and rate of oil
flow, it is essential that the following preliminary checks be
made.
1. Check oil level in transmission. This should be done with
oil temperature at 82 to 93 °C (180 to 200 °F). Do not
attempt these checks with cold oil.
2. To bring the oil temperature to this level, it is necessary
to either work the machine or stall out the converter.
When it is impractical to work the machine, stall out the
converter as follows.
a. Apply the parking brake.
b. Position the shift lever to forward and high speed.
c. Accelerate the engine to between half and three-
quarter throttle.
d. Hold converter stalled until desired temperature is
reached.
NOTE: Always make all troubleshooting checks with the
converter outlet temperature at least 82.3 to 93.3
°C (180 to 200 °F).
CAUTION
Full throttle stall speeds for an excessive length of time
will overheat the torque converter.
Reference Only
To Next Page
Loading...
Need help?
General
