Acura RL. Manual - part 748

Fig. 16: Acceleration System Hydraulic Pressure Control Diagram - Straight Line 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

Cornering 

The solenoid valve is energized, applying hydraulic pressure to the high clutch piston via the shift valve to 
engage the high clutch. An accumulator and an orifice are installed between the shift valve and the high 
clutch piston to reduce the fluctuations in hydraulic pressure.

 

2007 Acura RL 

2005-08 DRIVELINE/AXLES Rear Differential - RL

  

me 

 

Friday, June 05, 2009 3:02:18 PM

Page 19 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 17: Acceleration System Hydraulic Pressure Control Diagram - Cornering 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

When backing up 

The reverse rotation of the propeller shaft causes the oil pump to rotate in reverse. This opens the reverse 
one-way valve and allows the oil to circulate in the pump and valve body without draining the system. This 
prevents aeration of the oil which can delay the response of the differential.

 

2007 Acura RL 

2005-08 DRIVELINE/AXLES Rear Differential - RL

  

me 

 

Friday, June 05, 2009 3:02:18 PM

Page 20 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 18: Acceleration System Hydraulic Pressure Control Diagram - When Backing Up 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

ELECTROMAGNETIC CLUTCH SYSTEM 

Construction 

The electromagnetic clutch system is incorporated into the side case assemblies on both sides of the 
differential case. The system consists of the multi-plate clutches, the planetary gears, the pressure guides, 
the solenoid coil assembly (the search coil and the main coil), the armature assembly (the slider and the 
armature), and the yoke. 

ELECTROMAGNETIC CLUTCH COMPONENTS REFERENCE 

Components

Purpose

Multi-plate clutches

Convert thrust into torque, absorb wheel speed differences

Planetary gears

Magnify and convey clutch torque

Pressure guides

Reduce fluctuations in pressure

Search coils

Detect magnetic flux

Main coils

Generates magnetic fields

Slider

Centers the armature

Armature

Generates magnetic flux to generate thrust

Yoke

Generates magnetic flux to clamping force

 

2007 Acura RL 

2005-08 DRIVELINE/AXLES Rear Differential - RL

  

me 

 

Friday, June 05, 2009 3:02:18 PM

Page 21 

© 2005 Mitchell Repair Information Company, LLC. 

Fig. 19: Electromagnetic Clutch System Construction Diagram 
Courtesy of AMERICAN HONDA MOTOR CO., INC. 

Operation 

The SH-AWD control unit receives inputs from the PCM and the VSA modulator-control unit on the driving 
conditions via the CAN. The SH-AWD control unit sends signals to the main coils, which engage the 
electromagnetic clutches that connect the planetary gear set. This increases the torque applied to the rear 
wheels. The amount of current sent to the clutch is continuously varied as driving conditions change.

 

2007 Acura RL 

2005-08 DRIVELINE/AXLES Rear Differential - RL

  

me 

 

Friday, June 05, 2009 3:02:18 PM

Page 22 

© 2005 Mitchell Repair Information Company, LLC.