M Range - First Gear, Engine Braking

M Range - First Gear, Engine Braking

M Range - First Gear is commanded by the TCM when vehicle speed is low enough not to overrev the engine (calibratable in the TCM). Changes to the hydraulic and electrical system are as follows.

NOTE:
Power flow for M Range - First Gear is exactly the same as Drive and M Range First Gear, with the exception that the low and reverse clutch (B3) assembly is applied in order to achieve maximum engine braking. To minimize the amount of repetitive text, the description of M Range - First Gear, Engine Braking includes only those components that are different from the description of Drive and M Range - First Gear. For the remaining description of First gear hydraulic power flow, refer to Drive and M Range - First Gear.

MANUAL VALVE
In the A position, the manual valve routes line (2) pressure into the drive (19) fluid circuit exactly the same as in DRIVE (D) range.

LOW AND REVERSE CLUTCH (B3) ASSEMBLY APPLIES

Reverse Shift Solenoid (SS) Valve Assembly (SS)
The normally closed reverse SS valve assembly is energized, allowing fluid pressure in the S5 signal (18) fluid circuit to exhaust through the solenoid.

Shift Pressure Relay Valve
S5 signal (18) fluid is exhausted from the shift pressure relay valve and spring force moves the valve to the released position to allow drive or reverse (20) fluid to enter the reverse control (25) fluid circuit Reverse control (25) fluid pressure is routed through the B4 control valve and on to the B5 control valve.

B5 Control Valve
Reverse control (25) fluid is regulated through the B5 control valve into the B5 control 1 (37) fluid passage.

#5 Accumulator Check Valve Assembly
B5 control 1 (37) fluid pressure is routed to the #5 accumulator check valve assembly and moves the check valve against spring force in order to help cushion the apply of the low and reverse clutch.

Solenoid Relay Valve
B5 control 1 (37) fluid pressure passes through the solenoid relay valve into the B5 control 2 (38) fluid circuit. B5 control 2 (38) fluid pressure is then routed through the U1 shift valve and on to the M1 shift valve.

M1 Shift Valve
B5 control 2 (38) fluid passes through the M1 shift valve into the low and reverse clutch (24) fluid circuit.

Low and Reverse Clutch (B3) Assembly
Low and reverse clutch (24) fluid is routed to the low and reverse clutch piston to apply the low and reverse clutch plates.

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

M Range - First Gear, Engine Braking: