A power train having a gas turbine engine, a direct coupled multiratio transmission and an automatic trimmed shift control system having a manual valve, shift valves responsive to a torque demand signal provided by gas turbine engine compressor discharge pressure and an output speed signal and timed pressure increasing trimmer valves for establishing the ratio drives and a throttle controlled neutral to first drive pressure regulating and shift control providing when the manual valve is in drive position and the throttle is in an off position, idle fuel feed and zero pressure for a positive neutral, during throttle movement from off position to a low throttle position, continuing idle fuel feed and then a small fuel feed increase and a gradually increasing pressure in a low pressure range controlling the rate of low power engagement of first drive and during further throttle movement from low throttle to full throttle, low to full fuel feed trimmer valve timed increasing pressure in a higher pressure range for high power engagement of first drive and full high pressure for maintaining high power first drive fully engaged and increasing. The throttle pedal controlled pressure regulator is disabled to prevent low pressure range regulation and supply full pressure to the trimmed shift control system by pressure above a low speed to maintain high power drive for overrun braking, during reverse drive as gradual low power engagement of reverse is not required and above a low torque demand or compressor discharge pressure for low pressure regulation only at low engine torque and power engine output.