Acura RL. Manual - part 227

Fig. 46: Hydraulic Pressure Flow Diagram (D Position: Driving In 1st Gear)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

D Position: Shifting between 1st gear and 2nd gear

As the speed of the vehicle reaches the programmed value, the PCM turns shift solenoid valve A ON, and shift
solenoid valve A uncovers the port of shift solenoid valve A pressure (SA) to shift valve A. Shift solenoid
valves B and C remain ON. Shift valve A is moved to the right side to uncover the port of CPC A pressure (4A)
leading to the 2nd clutch. The PCM actuates A/T clutch pressure control solenoid valve A, and A/T clutch
pressure control solenoid valve A pressure (56) is applied to CPC valve A. CPC valve A regulates line pressure
(4), and line pressure (4) becomes CPC A pressure (4A). CPC A pressure (4A) flows to shift valve B via shift
valves C and A, and becomes 2nd clutch pressure (20) at shift valve B. The 2nd clutch is engaged by the CPC
pressure. The 1st clutch is also engaged, but no power is transmitted because of the one-way clutch.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

Friday, June 05, 2009 1:18:11 PM

Page 79

Fig. 47: Hydraulic Pressure Flow Diagram (D Position: Shifting Between 1st Gear And 2nd Gear)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

D Position: Driving in 2nd gear

The PCM turns shift solenoid valve C OFF, and shift solenoid valve C uncovers the port of shift solenoid valve
C pressure (SC) to shift valve C. Shift solenoid valves A and B remain ON. Shift valve C is moved to the right
side to switch the port of line pressure (4) and CPC A pressure (4A) leading to the 2nd clutch. CPC A pressure
(5B) (5K) changes to line pressure (5B) (5K) and 2nd clutch pressure (20) is changed to line pressure, and the
2nd clutch is engaged by the line pressure. The 1st clutch is also engaged, but no power is transmitted because
of the one-way clutch.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

Friday, June 05, 2009 1:18:11 PM

Page 80

Fig. 48: Hydraulic Pressure Flow Diagram (D Position: Driving In 2nd Gear)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

D Position: Shifting between 2nd gear and 3rd gear

As the speed of the vehicle reaches the programmed value, the PCM turns shift solenoid valve C ON, and shift
solenoid valve C covers the port of shift solenoid valve C pressure (SC) to shift valve C. Shift solenoid valves A
and B remain ON. Shift valve C is moved to the left side to switch the port of line pressure (4) and CPC A
pressure (4A) leading to the 2nd clutch. Shift valve C also uncovers the port of CPC B pressure (4B) leading to
the 3rd clutch. The PCM actuates A/T clutch pressure control solenoid valves A and B. A/T clutch pressure
control solenoid valve A pressure (56) is applied to CPC valve A, and A/T clutch pressure control solenoid
valve B pressure (57) is applied to CPC valve B. CPC valve B regulates line pressure (4"), and line pressure
(4") becomes CPC B pressure (4B). CPC B pressure flows to shift valve A via shift valves C and B, and
becomes 3rd clutch pressure (30) at shift valve A. The 2nd clutch pressure (20) is changed to CPC pressure, and
the 3rd clutch is engaged by the CPC pressure. The 1st clutch is also engaged, but no power is transmitted
because of the one-way clutch.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

Friday, June 05, 2009 1:18:11 PM

Page 81

Fig. 49: Hydraulic Pressure Flow Diagram (D Position: Shifting Between 2nd Gear And 3rd Gear)
Courtesy of AMERICAN HONDA MOTOR CO., INC.

D Position: Driving in 3rd gear

The PCM turns shift solenoid valve B OFF, and shift solenoid valve B uncovers the port of shift solenoid valve
B pressure (SB) to shift valve B. Shift solenoid valves A and C remain ON. Shift valve B is moved to the right
side to switch the port of line pressure (5C), CPC B pressure (5J) leading to the 3rd clutch, and 2nd clutch
pressure (20) releasing 2nd clutch pressure. CPC B pressure (5J) changes to line pressure (5J) and 3rd clutch
pressure (30) is changed to line pressure, and the 3rd clutch is engaged by the line pressure. The 1st clutch is
also engaged, but no power is transmitted because of the one-way clutch.

NOTE:

When used, "left" or "right" indicates direction on the hydraulic circuit.

2007 Acura RL

2005-08 TRANSMISSION Automatic Transmission - RL

Friday, June 05, 2009 1:18:11 PM

Page 82

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