Abstract: A power transmission has axially aligned torque transmitting mechanisms. Each torque transmitting mechanism has a backing plate slidably disposed on a spline formed in the housing of the power transmission. Each backing plate has a locating ring to limit the axial movement of the backing plate and therefore the members of the torque transmitting mechanism during engagement. The locating rings are disposed in an L-shaped groove such that the outer locating ring is narrower that the inner locating ring. The backing plate of one of the torque transmitting mechanisms has an outer segmented annular extension that is aligned with the narrower locating ring to prevent interference between the backing plates when the one torque transmitting mechanism is engaging.

Abstract: A control for a multi-speed transmission has a multiple gain trim valve that controls the engagement pressure rise in a selectively engageable torque transmitting mechanism. The trim valve has a valve spool and a plug valve longitudinally aligned in a valve bore such that four separate areas are present. One of the areas has the engagement pressure of the torque transmitting mechanism imposed thereon. Another of the areas has a control pressure imposed thereon and the remaining two areas are subjected to the trim pressure. The gain rate between the trim pressure and the engagement pressure determines the rapidity with which the torque transmitting mechanism is engaged. The control pressure reduces the effect of the trim pressure to provide a low gain rate until the product of the trim pressure and one of the areas is equal to or greater than the product of the control pressure and the area on which it operates.

Abstract: A pressure control valve system for a friction device has a regulator valve with a plurality of pressure feedback differential areas which are selectively pressurized during the engagement of a friction device to control the apply pressure at one rate during normal operation and at a higher rate during high torque demand operation. A plug valve is disposed adjacent the regulator valve to establish two variable control forces acting on the regulator valve in response to a variable control pressure. The combination of the differential areas and the plug valve permit the regulator valve to establish two distinct pressure gain functions, each of which has a knee or inflection point resulting in two pressure gain ratios.

Abstract: Power transmissions incorporate gear ratios including a plurality of forward ratios, a neutral condition and at least one reverse ratio. The establishment of each ratio is controlled by selectively engageable hydraulically operated friction devices, such as clutches and brakes. The interchange between forward ratios is controlled by the interchange of at least one friction device. The control elements to accomplish the establishment and interchange of the ratios include a pressure source, shift valve, solenoid control valves and pressure control valves. The solenoid valves are electrically actuated and the hydraulic portion of the control includes elements that permit continued operation of the transmission in selected ratios in the event of electrical discontinuance.