GM Service Manual Online
For 1990-2009 cars only
Table 1: Function of Components
Table 2: Operations of Clutches and Brakes
Table 3: Transmission Range Reference

Caution: Lack of basic knowledge of this powertrain when performing diagnostic procedures could result in incorrect diagnostic performance or damage to powertrain components. Do not attempt to diagnose a powertrain problem without this basic knowledge.

The new automatic transmission AISIN (81-40LE) is an electronically controlled 4-speed automatic transmission with lock-up mechanism.

The transmission is mainly composed of the torque converter with lock up clutch, newly developed 4-speed planetary gear unit, the hydraulic control system and the electric control system.

Hydraulic Control System

Based on the hydraulic pressure created by the oil pump, the TCM sends signals to the solenoid and the hydraulic control system governs the hydraulic pressure acting on the torque converter, planetary gear, clutches, and brakes in accordance with the vehicle driving conditions.

Function of Components


Object Number: 1225586  Size: MF

Function of Components

Component

Function

7

Forward Clutch

Connects the input shaft and front sun gear.

3

Direct Clutch

Connects the input shaft and planetary carrier.

5

Reverse Clutch

Connects the input shaft and rear sun gear.

6

O/D and 2nd Brake

Prevents rear planetary sun gear from turning either clockwise or counterclockwise.

4

2nd Brake

Prevents outer race of 8 from turning either clockwise or counterclockwise, thus preventing the rear sun gear turning counterclockwise.

2

1st and Reverse Brake

Prevents the planetary carrier from turning either clockwise or counterclockwise.

8

No. 1 One-Way Clutch

When 4 is operating, this clutch prevents rear sun gear from turning counterclockwise.

1

No. 2 One-Way Clutch

Prevents the planetary carrier from turning counterclockwise.

Planetary Gear

These gears change the route through which driving force is transmitted, in accordance with the operation of each clutch and brake, in order to increase or reduce the input and output speed.

Operations of Clutches and Brakes


Object Number: 1225587  Size: MF

Operations of Clutches and Brakes

Clutch and Brake

Operation

C1

Forward Clutch

Connects the intermediate shaft and the front sun gear.

C2

Direct Clutch

Connects the input shaft and the planetary carrier.

C3

Reverse Clutch

Connects the intermediate shaft and the rear sun gear.

B1

O/D and 2nd Brake

Lock rear sun gear

B2

2nd Brake

Lock rear sun gear

B3

1st and Reverse Brake

Lock planetary carrier

F1

1-Way Clutch No. 1

Lock counterclockwise rotation of the rear sun gear, when B2 operations

F2

1-Way Clutch No. 2

Lock counterclockwise rotation of the planetary carrier


Transmission Range Reference

Position

Solenoid

Clutch

Brake

One-Way Clutch

Shift 1

Shift 2

Timing

C1

C2

C3

B1

B2

B3

F1

F2

P

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

R

V less than 9 km/h (5 mph)

ON

ON

OFF

OFF

OFF

ON

OFF

OFF

ON

OFF

OFF

V greater than or equal to 9 km/h (5 mph)

ON

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

N

ON

ON

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

OFF

D

1st

ON

ON

OFF

ON

OFF

OFF

OFF

OFF

OFF

OFF

ON

2nd

ON

OFF

OFF

ON

OFF

OFF

OFF

ON

OFF

ON

OFF

3rd

OFF

OFF

OFF

ON

ON

OFF

OFF

ON

OFF

OFF

OFF

3-4

OFF

ON

ON-OFF

ON-OFF

ON

OFF

OFF-ON

ON

OFF

OFF

OFF

4th

OFF

ON

OFF

OFF

ON

OFF

ON

ON

OFF

OFF

OFF

2

1st

ON

ON

OFF

ON

OFF

OFF

OFF

OFF

OFF

OFF

ON

2nd

ON

OFF

OFF

ON

OFF

OFF

ON

ON

OFF

ON

OFF

3rd

OFF

OFF

OFF

ON

ON

OFF

OFF

ON

OFF

OFF

OFF

1

1st

ON

ON

OFF

ON

OFF

OFF

OFF

OFF

ON

OFF

ON

2nd

ON

OFF

OFF

ON

OFF

OFF

ON

ON

OFF

ON

OFF