Reverse Lockout Valve; Pump Cover; Primary Regulator Valve - SSANGYONG 2004 Rexton 2.7XDi Workshop Manual

3A2-14

Reverse lockout valve

The reverse lockout valve is a two position valve con-tained
in the upper valve body. This valve uses S1-S2 pressure
as a signal pressure and controls the applica-tion of the
rear band (B2).
While the manual valve is in D, 3, 2 or 1 positions, drive oil
is applied to the spring end of the valve, overriding any
signal pressures and holding the valve in the lockout
position. This prevents the application of B2 in any of the
forward driving gears except M1.
When the manual valve is in P, R or N positions, drive oil
is exhausted and the reverse lockout valve may be toggled
by S1-S2 pressure.
B2 is applied in P, R, and N if the following conditions are
satisfied;
• In P or N, vehicle speed = 3 km/h.
• In R, vehicle speed = 10 km/h.
• Engine speed = 1600 rpm.
• Throttle position = 12 %.
Under these conditions, the TCM switches solenoids S1
and S2 to OFF. The reverse lockout valve toggles under
the influence of the S1-S2 pressure, to connect the line
pressure to the B2 feed. Oil is fed to both the inner and
outer apply areas of the rear servo piston, applying B2.
If any of the above conditions are not satisfied, the TCM
switches solenoids S1 and S2 to ON.
CHANGED BY
EFFECTIVE DATE
AFFECTED VIN
S1- S2 pressure is exhausted and the valve is held in the
lockout position by the spring. In this position, engage-
ment of B2 is prohibited.
This feature protects the transmission from abuse by pre-
venting the undesirable application of B2 at high speed,
and by providing a reverse lockout function.
Note that if the transmission is in failure mode, the rear
band will be applied at all times in P, R and N.

Pump cover

Y220_3A2170

Primary regulator valve

The Primary Regulator Valve (PRV) regulates the trans-mis-
sion line pressure (or pump output pressure). This valve
gives either high or low line pressure depending on whether
S6 is switched OFF or ON. When S6 is switched ON, S6
pressure is applied to the PRV moving it against spring
pressure and opening the line pressure circuit to the pump
suction port resulting in reduced line pressure.
Low line pressure is used during light throttle applica-tions
and cruising. Heavy throttle will cause S6 to switch OFF
and thereby cause high line pressure.
This stepped line pressure control has no detrimental ef-
Y220_3A2180
fect on shift feel because all shifting pressures are con-
trolled by separate band and clutch regulator valves, and
the output of S5.
When reverse gear is selected, both the low and high line
pressure values are boosted to guard against slip-page.
This is achieved by applying reverse oil line pressure to
the PRV to assist the spring load. The other end of the
valve contains ports for line pressure feedback and S6
pressure.
The PRV also regulates the supply of oil to the converter via
the converter feed port. The cascade effect of the PRV en-
sures the first priority of the valve is to maintain line pres-
sure at very low engine speeds. When the engine speed
increases and the pump supplies an excess of oil the PRV
moves to uncover the converter feed port thereby pressuriz-
ing the converter. If there is an excess of oil for the
transmission's needs then the PRV moves further to allow
oil to return to the suction port.
Y220_3A2190
BTRA 4 AUTO TRANSMISSION
REXTON SM - 2004.4