GM Service Manual Online
For 1990-2009 cars only

With the gear selector lever in the PARK (P) position and the engine running, the line pressure from the fluid pump assembly is directed to various components in the control valve body assembly and the transmission case assembly.

FLUID PRESSURE DIRECTED IN PREPARATION FOR A SHIFT

Manual Valve

Mechanically controlled by the gear selector lever, the manual valve is in the PARK (P) position and prevents line (2) pressure from the primary regulator valve from entering the drive (19) and reverse (22) fluid circuits.

Reverse, 1st Shift Solenoid (SS) Valve Assembly (S1)

Line (2) fluid passes through orifice #3 into the S1 signal (14) fluid circuit in preparation for a shift. The normally open reverse, 1st SS valve assembly is OFF, allowing any fluid pressure in the S1 signal (14) fluid circuit to exhaust through the solenoid.

3-4, 4-5 Shift Solenoid (SS) Valve Assembly (S4)

Line (2) fluid passes through orifice #4 into the S4 signal (17) fluid circuit in preparation for a shift. The normally open 3-4, 4-5 SS valve assembly is OFF, allowing any fluid pressure in the S4 signal (17) fluid circuit to exhaust through the solenoid.

Reverse Shift Solenoid (SS) Valve Assembly (S5)

Line (2) fluid passes through orifice #5 into the S5 signal (18) fluid circuit. The normally closed reverse SS valve assembly is OFF, causing fluid pressure to build-up in the S5 signal (18) fluid circuit.

Shift Pressure Relay Valve

S5 signal (18) fluid is routed to the shift pressure relay valve and applies the valve against spring force.

1-2 REVERSE CLUTCH (B5) APPLIES

U1 Shift Valve

Line (2) fluid is also routed to the U1 shift valve and passes through the valve into the 1-2 reverse clutch (39) fluid circuit.

1-2 Reverse Clutch (B5) Assembly

1-2 reverse clutch (39) fluid enters the automatic transmission case cover assembly and moves the 1-2 reverse clutch piston against spring force to apply the 1-2 reverse clutch plates. In PARK range, the 1-2 reverse clutch has no effect. However, when REVERSE or a forward range is selected, only one apply device has to be energized, which helps create a smooth starting motion.

FLUID PRESSURE DIRECTED TO PREVENT TCC APPLY

Lock Up Relay Valve

1-2 reverse clutch (39) fluid is also routed to the lock up relay valve. Here it assists converter feed (3) fluid pressure and spring force to hold the valve in the released position, thus preventing torque converter clutch apply.

PASSAGES

  1. SUCTION
  2. LINE
  3. CONVERTER FEED
  4. RELEASE
  5. APPLY
  6. EXHAUST ENABLE
  7. COOLER
  8. LUBE
  9. SOLENOID MODULATOR
  10. THROTTLE SIGNAL (SLT)
  11. SHIFT CONTROL (SLS)
  12. LOCK UP CONTROL (SLU)
  13. TCC SIGNAL
  14. S1 SIGNAL
  15. S2 SIGNAL
  16. S3 SIGNAL
  17. S4 SIGNAL
  18. S5 SIGNAL
  19. DRIVE
  20. DRIVE OR REVERSE
  21. REGULATED DRIVE OR REVERSE
  22. REVERSE
  23. REVERSE CLUTCH
  24. LOW AND REVERSE CLUTCH
  25. REVERSE CONTROL
  26. FORWARD CLUTCH
  27. DIRECT CLUTCH FEED 1
  28. DIRECT CLUTCH FEED 2
  29. DIRECT CLUTCH
  30. B2 CONTROL 1
  31. B2 CONTROL 2
  32. SECOND CLUTCH
  33. B1 CONTROL 1
  34. B1 CONTROL 2
  35. B1 CONTROL 3
  36. SECOND COAST CLUTCH
  37. B5 CONTROL 1
  38. B5 CONTROL 2
  39. 1-2 REVERSE (B5) CLUTCH
  40. 4-5 CLUTCH
  41. B4 CONTROL
  42. B4 RELEASE
  43. SERVO RELEASE
  44. SERVO FEED
  45. SERVO APPLY
  46. 3RD GEAR BAND APPLY
  47. PN12345
  48. PRN15
  49. 234NCON
  50. 345 ENABLE
  51. 45 ENABLE
  52. REVERSE INHIBIT
  53. VENT
  54. EXHAUST
  55. SUMP
  56. VOID
  57. TORQUE CONVERTER SEAL DRAINBACK

Park - Engine Running


Object Number: 1254594  Size: FS