This system charges the converter.
When the engine RPM is reduced and the
converter turbine attempts to rotate
When the desired pressure is reached in
this system, the converter pressure reg-
faster than the pump, the sprag-type
clutch locks up. This connects the con-
ulator valve opens and allows excess oil
verter output shaft mechanically to the
to return to the inlet side of the pump.
engine, utilizing full engine compression
In coming oil from the oil pump flows
for lowering light loads. The clutch re-
through internal passageways in the
leases instantly when engine power is
converter housing and through the
applied to the machinery.
ground sleeve. It enters the converter
elements between the converter pump
and stator. The oil leaves the converter
elements between the turbine and stator
P r e v e n t a t i v e Maintenance
and flows inside the ground sleeve along
CHECKING CONVERTER-IN OIL PRES-
the output shaft and out through a pas-
SURE. The charging oil pump pressure
sageway in the converter housing to the
(converter-in) should be 50 psi (345
oil reservoir by way of the oil filter and
kPa) and 80 psi (552 kPa) maximum at
oil cooler.
full throttle stall condition. The maxi-
mum
permissible
pressure
at
full
OPERATION.. The torque converter
throttle, no load, is 120 psi (827 kPa)
functions in two distinct phases - multi-
It is most important that the values not
plying torque hydraulically and operat-
exceed the limits given. This pressure
ing
as
a
fluid
coupling.
The
load
can be checked at either of the two con-
deter-mines the phases in which the con-
verter-in pressure check points
verter operates.
(Figure 4C-4 on page 4C-7) on the
charging oil pump. If the pressure is
Converter phase means that the stator is
not normal, refer to Table 4C-1 on page
stationary [locked up). As a result, the
greatest possible torque multiplication of
input torque to output torque is taking
METAL CONTAMINATION OF OIL. If the
place.
oil in the hydraulic system becomes con-
taminated with metal particles, all the
Since the stator is stationary (locked
components of the hydraulic system -
up), the oil leaving the turbine is di-
torque converter, oil lines, filters, res-
rected back to the pump by the vanes of
ervoir, strainer, cooler, valves and oil
the stator in the same direction the pump
pumps. must be thoroughly cleaned
This redirects oil flow then
is turning.
usually means overhaul of the compon-
aids the pump and is the key to torque
ents. Metal particles in the oil (except
for the minute particles normally trapped
in the oil filter) are evidence of failure
The torque converter goes into the fluid
of some part, either in the converter or
coupling phase as t h e t u r b i n e s p e e d
in the transmission.
nears the speed of the pump. Since the
turbine is connected directly to the out-
CHECKING FOR LOCKED STATOR. If it
put shaft, as the demand for torque mul-
should become necessary to check for a
tiplication decreases, the flow of oil
locked stator by observing temperature
wihtin the converter cahanges. This
drop rate, increase converter-out tem-
change of oil flow acts upon the opposite
perature to 230F (110C) by stalling the
side of the stator, causing it to free-
converter output shaft at full throttle
wheel. As the turbine speed approaches
Release the converter output shaft and
pump speed, the input torque to output
immediately c h e c k t h e r a t e o f t e m p e r -
torque ratio is approaching 1 to 1.
ature drop with no load on the converter
and maximum input RPM. Temperature
If the turbine slows down and the de-
should start to drop after 15 seconds.
mand for output torque increases, the
converter automatically multiplies torque.
A slow temperature drop rate indicates
The stator locks up, thus reverting to
that the stator probably is locked. A
converter phase operation.
rapid temperature drop rate indicates
normal stator operation.
In this unit the clutch is over running
(freewheeling) anytime the converter
CHECKING ENGINE CONVERTER
pump is driving the turbine.
ALIGNMENT. If the engine has been ov-
erhauled, or if the converter pilot bear-
