| 摘要 |
PURPOSE: To reliably prevent a shift to the gear ratio causing a state such as abrasion and seizure of a synchronizer of a transmission and an overspeed of an engine by sensing a present vehicle ground speed, and automatically mechanically blocking a shift to the first gear ratio when exceeding a prescribed maximum vehicle ground speed. CONSTITUTION: Assuming that a second reference value is 34 MPH and a first reference value is 13 MPH, when sensing a vehicle speed lower than 21 MPH, a controller 218 makes a blocking means take a completely retreating plunger position. When sensing a vehicle speed higher than 13 MPH but lower than 34 MPH, the controller 218 makes the blocking means 214 take an intermediate plunger extending position to set downshift to a first or second speed nonselectable. When sensing a vehicle speed over 34 MPH, the controller 218 makes the mechanical blocking means 214 take a completely extending plunger position to block the selection of the downshift to a fourth, third, second or first speed. |
