Abstract: A brake band shifting mechanism for an automatic transmission. The brake band shifting mechanism includes a brake band encircling a brake drum of the transmission. A first end of the brake band is mounted to a secured portion of the transmission by a first linkage and a second end of the brake band is mounted to a two-stage servo by a second linkage. The servo provides selective apply and release pressure to the second linkage to control the compression or expansion of the brake band. In operation, the brake band is quickly compressed to the brake drum during the first stage of the servo, and then fine adjustments are made to control the speed of the brake drum during the second stage of the servo, where inputs from position and speed sensors in the transmission are used to control the adjustment of the brake band.

Abstract: A brake band shifting mechanism for an automatic transmission. The brake band shifting mechanism includes a brake band encircling a brake drum of the transmission. A first end of the brake band is mounted to a secured portion of the transmission by a first linkage and a second end of the brake band is mounted to a two-stage servo by a second linkage. The servo provides selective apply and release pressure to the second linkage to control the compression or expansion of the brake band. In operation, the brake band is quickly compressed to the brake drum during the first stage of the servo, and then fine adjustments are made to control the speed of the brake drum during the second stage of the servo, where inputs from position and speed sensors in the transmission are used to control the adjustment of the brake band.

Abstract: An electro/hydraulic control system for automatically shifting gear stages of a multiple stage transmission gear mechanism by selectively controlling the operable effectiveness of various hydraulically operated friction units in accordance with vehicle operating conditions. The control system includes a series of hydraulic shift valves arranged in combination with at least two pressure regulator valves for controlling the supply of hydraulic actuating fluid to the friction units in response to ratio selection signals derived in an electronic control. The control system further includes at least one variable pressure solenoid whose variable pressure output is multiplexed to each pressure regulator valve in the system to provide for quality shifts between gear ratios. The desired end is effected by programmably profiling the output of the variable pressure solenoid.