Reverse is very similar to first gear, except that instead of the small sun gear being driven by the torque converter turbine, the bigger sun gear is driven, and the small one freewheels in the opposite direction. The planet carrier is held by the reverse band to the housing. So, according to our equations from the last page, we have:
Ratio = -R/S = 72/36 = 2.0:1So the ratio in reverse is a little less than first gear in this transmission.
Gear Ratios
This transmission has four forward gears and one reverse gear. Let’s summarize the gear ratios, inputs and outputs:
| Gear |
Input |
Output |
Fixed |
Gear Ratio |
| 1st |
30-tooth sun |
72-tooth ring |
Planet carrier |
2.4:1 |
| 2nd |
30-tooth sun |
Planet carrier |
36-tooth ring |
2.2:1 |
| Planet carrier |
72-tooth ring |
36-tooth sun |
0.67:1 |
|
|
Total 2nd |
1.47:1 |
| 3rd |
30- and 36-tooth suns |
72-tooth ring |
|
1.0:1 |
| OD |
Planet carrier |
72-tooth ring |
36-tooth sun |
0.67:1 |
| Reverse |
36-tooth sun |
72-tooth ring |
Planet carrier |
-2.0:1 |
After reading these sections, you are probably wondering how the different inputs get connected and disconnected. This is done by a series of clutches and bands inside the transmission.
