A shift mechanism for a change-speed gearing in a power transmission which includes a pneumatic or hydraulic actuator, a shift rod axially slidably carried on a support structure and operatively connected at a first end thereof with the actuator for reciprocating movement, and a mechanism for selectively establishing a drive power gear train in the transmission in response to the reciprocating movement of the shift rod. The support structure is formed at one side thereof with a cylindrical portion in which an axial bore is formed coaxially with the shift rod to contain a second end of the shift rod, and a plug is detachably threaded into the cylindrical portion of the support structure to close the axial bore. The plug is associated with a retainer element for retaining the shift rod in its rearward position by engagement with a second end of the shift rod.

A remote control mechanism connects the shifting lever of a motor vehicle to the vehicle gearbox or transmission, and has a drive member connected to the shifting lever, and a driven member operatively connected to the transmission shift rail. The drive member is supported for both linear motion for selecting a gear, and rotary motion for shifting into a gear. The driven member is supported for both linear motion and rotary motion. A push-pull cable transmits the linear motion of the drive member to the driven member, and master and slave hydraulic linear actuators transmit the rotary motion of the drive member to the driven member so that the transmission is responsive to the shifting lever being moved along two perpendicular paths of motion in a gear shifting pattern. In another embodiment, master and slave hydraulic linear actuators connect the drive and driven members for transmitting both the linear and the rotary motion of the drive member to the driven member.

A hydraulic apparatus for remotely controlling the operative mode selector of a motor vehicle automatic transmission. The apparatus comprises a master cylinder having an input member operatively connected to the transmission operative mode selection or shift lever placed at the disposal of the motor vehicle operator, and a slave cylinder mounted on or proximate the transmission casing and having an output member connected to the transmission operative mode selector, the master cylinder and the slave cylinder being placed in fluid communication through flexible conduits such that each displacement of the master cylinder piston as a result of displacement of the master cylinder input member causes a corresponding displacement of the slave cylinder piston coupled to the slave cylinder output member. After assembly of the components, the apparatus is filled with hydraulic fluid and, preferably, break-away restraining straps are installed to hold the master cylinder input member and the slave cylinder output member against extension beyond a limit.

Parallelly spaced apart shift rods are interlocked by balls between adjacent shift rods. Plungers are mounted on respective shift rods and received in bores communicating with a source of fluid under pressure through a valve which, when closed, blocks movements of the rods. The valve is opened when the driver sits on his seat and wears his safety seat belt, to unlock movements of the plungers in their bores as well as movements of the rods.

A transmission which is controlled by an electronic control unit for gear shift operation, said transmission comprising a shift actuator including a plurality of shift shafts for effecting engagement and disengagement of the transmission gears to accomplish a plurality of shift ranges and the same number of cylinders each being operatively connected with respective one of said shift shafts, said shift actuator being controlled by the signals from the electronic control unit for effecting the gear shift operation. Each of said shift shafts is operatively connected with a respective piston disposed in each cylinder by means of a select lever assigned to the piston and the shift shaft. The shift shafts axially move to engage and disengage the transmission gears. The cylinders are disposed parallel or coaxial with the shift shafts.