ETRS System Operation

Park: 

Solenoids F and G are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. Line pressure is directed by the transmission range control valves to the park on hydraulic circuit, which is used to assist the park servo return spring in overcoming the park servo apply fluid. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.

Reverse:

• Solenoids D, E, G, and PISA are on. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves.
• Solenoid D shuttles the transmission range control valve 2, allowing line pressure to enter the reverse hydraulic circuit feeding the clutch selector valve. The clutch selector valve directs the reverse fluid to the SOWC Servo which holds the SOWC during reverse. Solenoid E directs line pressure to the 57R Clutch.

Neutral (commanded with speed below a certain threshold):

• Solenoids F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. If shifting from Park to Neutral, solenoids C and D are on for 350 ms or less which shuttles the transmission range control valves, applying the park servo which disengages the parking pawl.
• If shifting to neutral from reverse or drive, the PISA is held on and the mode valves are returned to their default positions. Hydraulically, the system is in a Park state at this time. However, because the PISA was held on during the shift from R/D to Neutral, the parking pawl remains disengaged.

Neutral Shift (for unique conditions):

• Solenoids C, D, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission range control valve 1 to allow line pressure to enter the Feed 1 hydraulic circuit which applies the park servo, disengaging the parking pawl. Solenoid D shuttles the transmission range control valve 2, preventing Feed 1 fluid from entering the drive hydraulic circuit.

Neutral High (commanded with speed above a certain threshold):

• Solenoids D, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid D shuttles transmission range control valve 1 which allows Feed 0 fluid to enter the Reverse hydraulic circuit which applies the park servo, disengaging the parking pawl. The clutch selector valve is shuttled to prevent reverse fluid from applying any clutches.

Drive - 1st Gear - Lock - Engine Braking:

• Solenoids C, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.

Drive - 1st Gear - Freewheel:

• Solenoids C, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F allows line pressure to enter the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.

Drive - 2nd Gear:

• Solenoids B, C, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Solenoid B allows Drive fluid to enter the 29C hydraulic circuit, applying the 29C Clutch assembly.

Drive - 3rd Gear:

• Solenoids C, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C is PWM in order to create a pressure high enough to shuttle the transmission range control valve 1 and the 38C regulator valve. This allows Drive fluid to enter the clutch selector valve, which directs Drive fluid into the Drive 2 hydraulic circuit. The 38C Regulator valve directs Drive 2 fluid into the 38C hydraulic circuit applying the 38C Clutch assembly.
• The transmission control valve 1 allows line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.

Drive - 4th Gear:

• Solenoids C, D, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Solenoid D is PWM in order to create a pressure high enough to shuttle the transmission range control valve 1 and 4^th Clutch regulator valve. This allows Drive fluid to enter the clutch selector valve, which directs Drive fluid into the Drive 2 hydraulic circuit. The 4^th Clutch Regulator valve directs Drive 2 fluid into the 4^th Clutch hydraulic circuit applying the 4C Clutch assembly.

Drive - 5th Gear:

• Solenoids C, E, F, G, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost. Solenoid F prevents line pressure from entering the 1 Rev/6789C hydraulic circuit.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Drive 2 fluid enters the 57R Clutch Feed hydraulic circuit. Solenoid E allows 57R Clutch Feed to apply the 57RC Clutch Assembly.

Drive - 6th Gear:

• Solenoids C, G, H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Line pressure is now able to flow through Solenoid F into the 1 Rev/6789C Clutch Feed hydraulic circuit. 1 Rev/6789C Clutch Feed fluid is directed into 6789C Clutch hydraulic circuit by the Clutch Selector Valve, which applies the 6789C Clutch Assembly.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. The Drive fluid passes through Solenoid A and into the 123456C Clutch assembly.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.

Drive - 7th Gear:

• Solenoids A, C, E, G, H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Line pressure is now able to flow through Solenoid F into the 1 Rev/6789C Clutch Feed hydraulic circuit. 1 Rev/6789C Clutch Feed fluid is directed into 6789C Clutch hydraulic circuit by the Clutch Selector Valve, which applies the 6789C Clutch Assembly.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. Solenoid A does not allow Drive fluid to enter the 123456C Feed hydraulic circuit.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.
• Drive 2 fluid enters the 57R Clutch Feed hydraulic circuit. Solenoid E allows 57R Clutch Feed to apply the 57RC Clutch Assembly.

Drive - 8th Gear:

• Solenoids A, C, G, H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Solenoid C is PWM in order to create a pressure high enough to shuttle the transmission range control valve 1 and the 38C regulator valve. This allows Drive fluid to enter the clutch selector valve, which directs Drive fluid into the Drive 2 hydraulic circuit. The 38C Regulator valve directs Drive 2 fluid into the 38C hydraulic circuit applying the 38C Clutch assembly. Solenoid A does not allow Drive fluid to enter the 123456C Feed hydraulic circuit.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.
• Line pressure is now able to flow through Solenoid F into the 1 Rev/6789C Clutch Feed hydraulic circuit. 1 Rev/6789C Clutch Feed fluid is directed into 6789C Clutch hydraulic circuit by the Clutch Selector Valve, which applies the 6789C Clutch Assembly.

Drive - 9th gear:

• Solenoids A, B, C, G, H, and PISA are on. Solenoid G shuttles the mode enable valve to provide line pressure to transmission range control valves. The PISA is held on to prevent an unintentional parking pawl engagement if hydraulic pressure at the park servo is lost.
• Solenoid C shuttles the transmission control valve 1 allowing line pressure to enter Feed 1 hydraulic circuit, which directs fluid to the transmission control valve 2. The transmission control valve 2 directs Feed 1 fluid to the Drive hydraulic circuit. Solenoid A does not allow Drive fluid to enter the 123456C Feed hydraulic circuit.
• Solenoid H allows line pressure to enter the TCC VFS Hydraulic circuit, shuttling TCC Control Valve and TCC Reg Apply Valve.
• Solenoid B allows Drive fluid to enter the 29C hydraulic circuit, applying the 29C Clutch assembly.