A/T System Description

Overview

The automatic transmission has four planetary gear sets, three clutches, three brakes, and a two-way clutch, and allows the gears to change (ten-speed forward, one-reverse). The engine output is transmitted through the torque converter, the shafts which hold the planetary gear sets and the clutches, the differential assembly, and the transfer assembly (With AWD) that transmits the power to the driving wheels.

Without AWD

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With AWD

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Gear Change Mechanism

To change the gears, the TCM actuates the shift solenoid valves and the clutch pressure control solenoid valves in the valve body assembly, and switches hydraulic passages, then four planetary gear sets, three clutches, three brakes, and two-way clutch are engaged in a specific sequence by the hydraulic pressure.

Courtesy of HONDA, U.S.A., INC.

Clutch Connecting Condition Chart

Gear	Clutch			Brake			Two-Way Clutch
Gear	C1	C2	C3	B1	B2	B3	Two-Way Clutch
R
1
2
3
4
5
6
7
8
9
10

Park Mechanism

The park mechanism locks the transmission by engaging the parking brake pawl with the parking gear. When a P position command is received from the TCM, the detent lever (integrated with the control shaft) moves to the P position. The movement of the parking actuator arm moves the parking brake rod and the parking brake pawl to the P position, and engages the claw of the parking brake pawl with the parking gear.

Courtesy of HONDA, U.S.A., INC.

Lock-Up Mechanism

The lock-up causes the input shaft to rotate at the same speed as the engine crankshaft by coupling the torque converter directly, and improves fuel efficiency and durability. With the hydraulic control, the TCM optimizes the timing and degree of lock-up by controlling shift solenoid valve C and clutch pressure control solenoid valve H.

Shift Control

When the driver operates the SBW shifter assembly, the SBW shifter control module transmits a shift position signal to the TCM. Based on the signal received from the SBW shifter control module, the TCM actuates the shift solenoid valves and the clutch pressure control solenoid valves in the valve body assembly, and performs the shifting operation.

Gear Selection

The shift position/mode has five positions; P: PARK, R: REVERSE, N: NEUTRAL, D: DRIVE, and S: SPORT.

Shift Position Indicator

The shift position indicator in the gauge control module shows which shift position/mode has been selected without looking down at the console.

Automatic P Position/Mode Selection Control

The P position/mode is automatically selected for safety in the following cases;

A driver disconnects the seat belt and opens the door with any other position/mode than P position/mode while the vehicle speed is less than 1 mph (2 km/h) with the engine running.
A driver turns the vehicle to the OFF (LOCK) mode with any other position/mode than P position/mode while the vehicle speed is less than 1 mph (2 km/h) with the engine running.
A driver turns the vehicle to the OFF (LOCK) mode with any other position/mode than P position/mode while the vehicle speed is greater than 1 mph (2 km/h) with the engine running. The gear will first shift to N and automatically select P once the vehicle speed is less than 1 mph (2 km/h).

Neutral Position Holding Mode

This system is configured in such a way that the P position/mode is entered automatically when the vehicle is turned to the OFF (LOCK) mode. For this reason, a neutral position holding mode is provided when it is desired to stay in the N position/mode even when the vehicle is in the OFF (LOCK) mode. The neutral position holding mode keeps the transmission in the N position for approximately 15 minutes.

Function for Prevention of Erroneous Operation

A function for prevention of erroneous operation is provided to ensure that operating safety is maintained at all times, even in cases of a handling error in regard to the SBW shifter assembly.

Operations where the function for prevention of erroneous operation is activated	Shift position after the function for prevention of erroneous operation was activated
When the brake pedal is not pressed at the time of shifting from the P position/mode	P
When the accelerator pedal is pressed at the time of shifting from the P position/mode	P
When the brake pedal is not pressed at the time of shifting from the N position/mode	P or N
When the accelerator pedal is pressed at the time of shifting from the N position/mode	P or N
When the vehicle speed is above 1 mph (2 km/h) at the time of shifting to the P position/mode	N
When the vehicle speed is above 5 mph (8 km/h) at the time of shifting from the D position/mode to the R position/mode	N
When the brake pedal is not pressed at the time of shifting from the D position/mode to the R position/mode	N
When the vehicle speed is above 7 mph (12 km/h) at the time of shifting from the R position/mode to the D position/mode	N

Manual Shift Mode

The transmission is equipped with a D-paddle shift mode and a sequential sportshift mode. Both modes are entered by pressing the paddle shifter while driving.

D-Paddle Shift Mode

When the paddle shifter is pressed while in the D position/mode, the D-paddle shift mode comes into operation. The shift indicator displays the number of the current gear. At this time, during the high speed stage (above 8th gear), the transmission can be shifted down by skipping two-stage at minimum, depending on the driving conditions. In the D-paddle shift mode, the transmission can be shifted into a lower gear or a higher gear by pressing the paddle shifter. The D-paddle shift mode is canceled when the paddle shifter + (upshift switch) is held for several seconds, when the D position/mode is canceled, or when the TCM detects a steady cruise.

Sequential Sportshift Mode

When the paddle shifter is pressed while in the S position/mode, the sequential sportshift mode comes into operation. The shift indicator displays the number of the selected gear and the M indicator comes on. In the sequential sportshift mode, the driver can shift up and down manually by using the paddle shifters much like a manual transmission. The sequential sportshift mode is canceled when the paddle shifter + (upshift switch) is held for several seconds or when the S position/mode is canceled.