| 摘要 |
A control device of an automatic transmission has automatic shift ranges and manual setting ranges including a first speed gear position at which an engine brake is operable. The control device turns on all solenoid valves at the first speed gear position in the automatic shift driving range, turns on only the second and third solenoid valves at the first speed gear position in the manual setting range, and turns on at least one of the three solenoid valves in normal operation. This prevents a shock resulting from a shift and easily starts a vehicle even if all of the three solenoid valves supplying oil pressure to the first through third shift valves for changing gear positions are turned off. Oil channels are preset in such a manner as to achieve a high speed gear position if no oil pressure is supplied to all shift valves. If all solenoid valves are turned off in the manual setting range, low speed gear position selecting oil channels supplied with an oil pressure from a manual valve are connected to the second and third shift valves through a failsafe valve so that the gear position can be shifted to the first speed gear position at which the engine brake is operable. |
