1991 ACURA NSX Service Repair Manual

COUNTERSHAFT 2ND GEAR

COUNTERSHAFT 3RD GEAR

3RD CLUTCH

DRIVE PLATE

LOCK-UP

CLUTCH

SECONDARY SHAFT

(cont'd)
FINAL DRIVEN GEAR
SECONDARY SHAFT 2ND GEAR

SECONDARY SHAFT 3RD GEAR
2ND CLUTCH
COUNTERSHAFT 4TH GEAR
COUNTERSHAFT REVERSE GEAR
PARKING GEAR
COUNTERSHAFT 1ST GEAR
ONE-WAY CLUTCH
1ST-HOLD CLUTCH
COUNTERSHAFT
MAINSHAFT
1ST CLUTCH
MAINSHAST 1ST GEAR
MAINSHAFT REVERSE GEAR
MAINSHAFT 4TH GEAR
4TH CLUTCH
MAINSHAFT 3RD GEARProCarManuals.com

Description

Clutches (cont'd)

Lock-up Clutch

1. Operation (clutch on)

With the lock-up clutch on, the oil in the chamber between the converter cover and lock-up piston is discharged, and the

converter oil exerts pressure through the piston against the converter cover. As a result, the converter turbine is locked on the

converter cover firmly. The effect is to bypass the converter, thereby placing the car in direct drive.

The power flows by way of:

2. Operation (clutch off)

With the lock-up clutch off, the oil flows in the reverse of CLUTCH ON. As a result, the lock-up piston is moved away from the

converter cover; that is, the torque converter lock-up is released.

Engine

To oil cooler

INLET
To oil cooler

INLET

OUTLET
TORQUE CONVERTER

COVER COMP
LOCK-UP PISTON

DAMPER SPRING

Engine

Drive plate

Torque converter cover

Lock-up piston

Damper spring

Turbine

Mainshaft

Drive plate

Torque converter cover

Pump

Turbine

MainshaftProCarManuals.com

Power Flow

MAINSHAFT REVERSE GEAR
MAINSHAFT 1ST GEAR

1ST CLUTCH

1ST-HOLD CLUTCH

ONE-WAY CLUTCH COUNTERSHAFT 1ST GEAR PARKING GEAR
COUNTERSHAFT REVERSE GEAR COUNTERSHAFT 4TH GEAR
2ND CLUTCH
SECONDARY SHAFT 2ND GEAR SECONDARY SHAFT 3RD GEAR FINAL DRIVEN GEAR
(cont'd)

FINAL DRIVE GEAR
TORQUE CONVERTER
3RD CLUTCH
COUNTERSHAFT
3RD CLUTCH COUNTERSHAFT
2ND GEAR
4TH CLUTCH

MAINSHAFT

3RD GEAR

MAINSHAFT

4TH GEAR

O: Operates, x : Doesn't operate.

Although the 1st clutch engages, driving power is not transmitted as the one-way clutch slips.ProCarManuals.com

Description

Power Flow (cont'd)

Position

At position, hydraulic pressure is applied to the 1st clutch and to the 1st-hold clutch.

The power flow when accelerating is as follows;

1. Hydraulic pressure is applied to the 1st clutch on the mainshaft and power is transmitted via the 1st clutch to the

mainshaft 1st gear.

2. Power transmitted to the mainshaft 1st gear is conveyed via the countershaft 1st gear to the one-way clutch on

the inside of the countershaft 1st gear. The one-way clutch is used to drive the countershaft.

3. Power is transmitted to the final drive gear and drives the final driven gear.

Hydraulic pressure is applied to the 1st-hold clutch but the countershaft is rotated by the one-way clutch.

The power flow when decelerating is as follows;

1. Rolling resistance from the road surface through the rear wheels to the final drive gear, then to the countershaft

1st gear via the Ist-hold clutch which is applied during deceleration.

2. The one-way clutch becomes free at this time because of the countershaft rotates in reverse at the time of accelerating.

3. The counterforce conveyed to the countershaft 1st gear turns the mainshaft 1st gear. At this time, since hydraulic

pressure is also applied to the 1 st clutch, counterforce is also transmitted to the mainshaft. As a result, engine braking

can be obtained with 1st gear.

1ST CLUTCH

MAINSHAFT 1ST GEAR

MAINSHAFT
TORQUE CONVERTER

COUNTERSHAFT

FINAL DRIVEN GEAR
1ST-HOLD CLUTCH

COUNTERSHAFT 1ST GEAR

ONE-WAY CLUTCH

FINAL DRIVE GEARProCarManuals.com

1. Power from the mainshaft 3rd gear drives the countershaft 3rd gear. Since at this time there is no hydraulic pressure

to the 3rd clutch. The countershaft 3rd gear turns freely and drives the secondary shaft 3rd gear.

2. The power is also transmitted to the secondary shaft 2nd gear because hydraulic pressure is applied to 2nd clutch.

3. The secondary shaft 2nd gear drives the countershaft 2nd gear. Power is transmitted to the final drive gear and

drives the final driven gear.

1ST CLUTCH

MAINSHAFT 3RD GEAR
MAINSHAFT 3RD GEAR

MAINSHAFT

COUNTERSHAFT

FINAL DRIVE GEAR

(cont'd)
FINAL DRIVEN GEAR
SECONDARY SHAFT 3RD GEAR
SECONDARY SHAFT 2ND GEAR
2ND CLUTCH
SECONDARY SHAFT
ONE-WAY CLUTCH
Position is provided to drive only in 2nd speed.

TORQUE CONVERTER
NOTE:

At position, hydraulic pressure is also applied to the 1st clutch, but since the rotation speed of the 2nd gear

exceeds that of 1st gear, power from 1st gear is cut off at the one-way clutch.

Power flow in position, 2nd speed is the same as position.ProCarManuals.com

Description

Power Flow (cont'd)

2. Power is transmitted to the final drive gear and drives the final driven gear.

MAINSHAFT 1ST GEAR

1ST CLUTCH

MAINSHAFT 3RD GEAR

MAINSHAFT
TORQUE CONVERTER

COUNTERSHAFT

FINAL DRIVE GEAR

FINAL DRIVEN GEAR
3RD CLUTCH
COUNTERSHAFT 3RD GEAR
ONE-WAY CLUTCH
Position is provided to drive only in 3rd speed.

At 3 position, hydraulic pressure is also applied to the 1st clutch, but since the rotation speed of the 3rd gear

exceeds that of 1st gear, power from 1st gear is cut off at the one-way clutch.

Power flow in position, 3rd speed is the same as position.ProCarManuals.com

In position, the optimum gear is automatically selected from the gear ratios of 1st, 2nd 3rd and 4th speeds, according
to conditions such as the balance between throttle opening (engine load) and vehicle speed.
1ST CLUTCHMAINSHAFT 1ST GEAR
MAINSHAFT
TORQUE CONVERTER
COUNTERSHAFT
FINAL DRIVE GEAR
(cont'd)
FINAL DRIVEN GEAR

PARKING GEAR

COUNTERSHAFT

1ST GEAR

ONE-WAY CLUTCH
Position, 1st speed
1 . Hydraulic pressure is applied to the 1st clutch, which rotates together with the mainshaft, and the mainshaft 1st gear rotates.
2. Power is transmitted to the countershaft 1st gear, and drives the countershaft via the one-way clutch.
3. Power is transmitted to the final drive gear and drives the final driven gear. NOTE: In the position, hydraulic pressure is not applied to the 1st-hold clutch.ProCarManuals.com

Description

Power Flow (cont'd)

1 . Hydraulic pressure is applied to the 4th clutch, which rotates together with the mainshaft, and the mainshaft 4th

gear rotates.

2. Power is transmitted through countershaft 4th gear to the countershaft.

3. Power is transmitted to the final drive gear and drives the final driven gear.

NOTE: At position, 4th speed, hydraulic pressure is also applied to the 1 st clutch, but since the rotation speed of

4th gear exceeds that of 1st gear, power from 1st gear is cut off at the one-way clutch.

1ST CLUTCH

MAINSHAFT

1ST GEAR
MAINSHAFT

4TH GEAR

4TH CLUTCH

MAINSHAFT
TORQUE CONVERTER

COUNTERSHAFT

FINAL DRIVE GEAR

FINAL DRIVEN GEAR
COUNTERSHAFT 4TH GEAR
ONE-WAY CLUTCH
Position, 4th speedProCarManuals.com