Valve Body: Description and Operation
VALVES IN THE VALVE BODYThe valve body contains: the accumulator valve, the actuator limit valve, the TCC apply valve, the manual valve, the 3 - 4 shift valve, the 2 - 3 shift valve, and the 1 - 2 shift valve.
Torque Signal Compensatory Valve
This valve is located in the accumulator housing, and torque signal fluid pressure is fed to it in each gear range. The spring in the valve dampens any pressure irregularities in the torque signal fluid pressure that are caused by the operation of the force motor.
Checkball Valves
There are 11 checkball valves, located in the valve block and transmission case, see Figs. 1 and 2. The function of each is described below.
(1) Overrun Clutch
Seats to direct D321 fluid through an orifice and into the overrun clutch, thereby helping to control the apply rate of the overrun clutch. When the overrun clutch releases, the exhausting fluid unseats and flows past the checkball and into the D321 circuit. This allows a faster exhaust of fluid and a quicker release of the overrun clutch.
(2) Second Accumulator
Seats to direct accumulator fluid through an orifice before entering the second gear accumulator circuit, helping to control the rate at which the second gear clutch fluid exhausts from the rear servo and the release rate of the intermediate clutch.
(3) Front Band Apply
Seats to direct Front Band Apply fluid through an orifice to help control the apply rate of the front band. When the band releases, the exhausting fluid unseats and flows past the checkball, thus allowing a faster release of the front band.
(4) Second Gear Clutch
Seats to direct 2-3 fluid through an orifice and into the second gear clutch (intermediate clutch circuit; this helps to control the apply rate of the intermediate clutch. When the clutch releases, the exhausting fluid unseats and flows past the checkball and into the 2-3 circuit, allowing a faster exhaust of fluid and a quicker release of the intermediate clutch.
(5) Third Accumulator
Seats to direct accumulator fluid through an orifice before entering the third accumulator circuit. This helps to control the rate at which the third clutch fluid exhausts from the accumulator and the release rate of the direct clutch.
(6) Fourth Accumulator
Seats to direct accumulator fluid through an orifice before entering the fourth accumulator circuit; this helps to control the rate at which the fourth clutch fluid exhausts from the accumulator and the release rate of the fourth clutch.
(7) Low / Reverse (Shuttle Valve)
Allows Low fluid to enter the Rear Band Apply circuit, when manual first has been selected (not selectable currently), or Reverse fluid, to enter the rear band apply circuit.
(8) Third Gear Clutch
Seats to direct accumulator fluid through an orifice and into the third clutch circuit; this helps to control the apply rate of the direct clutch in third gear. When the clutch releases, the exhausting fluid unseats and flows past the checkball and into the third clutch circuit, allowing a faster exhaust of fluid and a quicker release of the direct clutch.
(9) Reverse
Seats to direct reverse fluid through an orifice; this helps to control the apply rate of the direct clutch in reverse gear. When the clutch releases, the exhausting fluid unseats and flows past the checkball, allowing a faster exhaust of fluid and a quicker release of the fourth clutch.
(10) Fourth Clutch
Seats to direct reverse fluid through an orifice; this helps to control the rate at which the fourth clutch is applied. When the fourth clutch releases, the exhausting fourth clutch fluid unseats and flows past the checkball, allowing a faster exhaust of fluid and a quicker release of the fourth clutch.
(11) Third Clutch / Reverse (Shuttle Valve)
Allows either, third clutch fluid (when third gear has been selected), or Reverse fluid, to enter the third / reverse circuit.
Active Components For Each Gear Ratio
Active Components For Each Gear:
Note: This table is in two parts for convenience only: the upper table for Park, Neutral, Reverse and Drive for all automatic forward gears, and the lower table for Manual 3 and Manual 2 gear ranges.