Specifications

Power Train Systems Operation 24
Neutral Position
When the transmission is in NEUTRAL position with
the engine running, oil is pulled from reservoir and the
strainer assembly (1) to pump (2). From there, pump
oil flows through the primary filter (3) to main relief
valve (4). Oil will also flow through orifice (18) to
lubricate the torque converter during hot, low speed
conditions.
When the pump pressure reaches 895 kPa (130 psi),
relief valve spool (4A) will move to the left side and
most of the pressure oil flows to the torque converter.
Spool will move left and right to maintain 895 kPa (130
psi). Oil can also bypass the torque converter through
converter bypass orifice (16). The purpose of orifice
(16) is to prevent too much of a pressure load being
put on the torque converter.
Oil flows from the torque converter through a passage
to oil cooler (17). Oil then flows back to transmission to
cool and lubricate the clutches and shaft bearings.
In NEUTRAL position, the remaining pressure oil flows
from main relief valve (4) to inching valve (6).
Without inching (inching pedal up and valve in), oil
flows around and through the center of spool (6A) to
the bottom of the spool. The oil, at the bottom, pushes
the spool to the position shown. Oil flows around the
lands of the spool and through a passage to
modulating valve (7).
In NEUTRAL position, forward solenoid (9) and
reverse solenoid (10) are OFF. Pump oil flow is
blocked at the solenoids. Oil cannot flow through oil
passage to the forward or reverse selector spool.
Pump oil pressure is felt at slugs. This forces forward
selector spool to the right and reverse selector spool
to the left. With the spools in this position, forward
clutch (11) and reverse clutch (12) are open to drain.
Most of the oil still flows through the lube circuit.