Honda Ridgeline. Manual - part 160
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General Operation
Torque Converter, Shafts, Gears, and Clutches
Electronic Control
Hydraulic Control
Shift Control Mechanism
14-25
System Description
The automatic transmission is a combination of a three-element torque converter and a four-shaft electronically
controlled unit which provides five forward and one in reverse. The entire unit is positioned in line with the engine.
The torque converter consists of a pump, turbine, and stator assembly in a single unit. The converter housing (pump)
is connected to the engine crankshaft and turns as the engine turns. Around the outside of the torque converter is a
ring gear which meshes with the starter pinion when the engine is being started. The entire torque converter assembly
serves as a flywheel, transmitting power to the transmission mainshaft. The transmission has four parallel shafts; the
mainshaft, the countershaft, the secondary shaft, and the intermediary shaft. The mainshaft is in line with the engine
crankshaft. The mainshaft includes the 4th and 5th clutches, and gears for 3rd, 4th, 5th and reverse (reverse gear is
integral with 5th gear). The countershaft includes gears for the final drive, 2nd, idler, 1st, 4th, 5th, and reverse (the final
drive gear is integral with the countershaft). The secondary shaft includes the 1st, 1st-hold, and 2nd clutches, and
gears for park, 2nd, idler, and 1st. The intermediary shaft includes the 3rd clutch, and gears for 3rd and 4th. The
countershaft 5th gear and the countershaft reverse gear can be locked to the countershaft at its left end, providing 5th
gear or reverse, depending with which way the selector is moved. The gears on the mainshaft, secondary shaft, and
intermediary shaft are in constant mesh with those on the countershaft. When certain conditions of gears in the
transmission are engaged by the clutches, power is transmitted through the mainshaft, and/or to the secondary shaft,
intermediary shaft, then to the countershaft to provide drive.
The electronic control system consists of the powertrain control module (PCM), sensors, and seven solenoid valves.
Shifting and lock-up are electronically controlled for comfortable driving under all conditions. The PCM is located in
the engine compartment.
The valve bodies include the main valve body, the secondary valve body, the regulator valve body, and the
accumulator body. They are bolted to the torque converter housing. The main valve body contains the manual valve,
the modulator valve, the torque converter check valve, shift valves A, B, D, and E, CPC valve C, the cooler check valve,
the relief valve, the lock-up shift valve, the lock-up timing valve, the lubrication control valve, the lubrication check
valve, and the ATF pump gears. The secondary valve body contains shift valve C, CPC valves A and B, the reverse CPC
valve, the servo control valve, and the kick-down valve. The regulator valve body contains the regulator valve, the
lock-up control valve, and the 3rd accumulator. The accumulator body contains the 1st, 1st-hold, 2nd, 4th, and 5th
accumulators, shift solenoid valves A, B, and C, and the torque converter clutch solenoid valve. Fluid from the
regulator passes through the manual valve to the various control valves. All the clutches receive fluid from the internal
hydraulic circuit.
To shift gears, the PCM controls shift solenoid valves A, B, and C, and automatic transaxle (A/T) clutch pressure
control solenoid valves A and B, while receiving input signals from various sensors and switches located throughout
the vehicle. The shift solenoid valves shift the positions of the shift valves to switch the port to send hydraulic pressure
to the clutches. The A/T clutch pressure control solenoid valves A and B control the CPC valves A and B to shift
smoothly between lower gear and higher gear. This pressurizes a line to one of the clutches, engaging the clutch and
its corresponding gear.
(cont’d)