The unavoidable trade-off using this type of arrangement was low efficiency and inevitably these transmissions were discontinued in favor of the greater productive three velocity units with a conventional 3 component torque converter. The torque converter must shift the vehicle ahead with just a light touch from the accelerator pedal. https://torqueconverterclutch07529.mybuzzblog.com/13412449/details-fiction-and-torque-converter-clutch