Power Flows
Operation of the transmission is controlled by the Transmission Control Module (TCM), which electrically activates various solenoids to control the transmission gear selection. The sequence of solenoid activation is based on programmed information in the TCM memory and physical transmission operating conditions such as:
- Vehicle speed
- Throttle position
- Engine load
- Selector lever position.
All gear shifts from 1st to 8th and 8th to 1st are known as 'overlap' shifts. Overlap shifts are during a gear shift one clutch must remain capable of transmitting torque at a reduced main pressure until the other clutch is ready to accept the torque.
Schematic Diagram - Power Flow
| ITEM | DESCRIPTION |
|---|---|
| A | Multiplate brake |
| B | Multiplate brake |
| C | Multiplate clutch |
| D | Multiplate clutch |
| E | Multiplate clutch |
| 1 | Ring gear of planetary gear set 1 |
| 2 | Planetary gears of planetary gear set 1 |
| 3 | Sun gear of planetary gear set 1 |
| 4 | Ring gear of planetary gear set 2 |
| 5 | Planetary gears of planetary gear set 2 |
| 6 | Sun gear of planetary gear set 2 |
| 7 | Ring gear of planetary gear set 3 |
| 8 | Planetary gears of planetary gear set 3 |
| 9 | Sun gear of planetary gear set 3 |
| 10 | Ring gear of planetary gear set 4 |
| 11 | Planetary gears of planetary gear set 4 |
| 12 | Sun gear of planetary gear set 4 |
| 13 | Power input from torque converter |
| 14 | Power output to output shaft |
Engine torque is transferred, via operation of single or combinations of clutches to the four planetary gear trains. All gear trains are controlled by reactionary inputs from brake clutches to produce the eight forward gears and the reverse gear.
The ratios are as follows:
| GEAR | 1ST | 2ND | 3RD | 4TH | 5TH | 6TH | 7TH | 8TH | REVERSE |
|---|---|---|---|---|---|---|---|---|---|
| Ratio | 4.714 | 3.143 | 2.106 | 1.667 | 1.285 | 1.000 | 0.839 | 0.667 | -3.295 |