Page "Torque converter" Paragraph 27

Some torque converters use multiple stators and / or multiple turbines to provide a wider range of torque multiplication.

Such multiple-element converters are more common in industrial environments than in automotive transmissions, but automotive applications such as Buick's Triple Turbine Dynaflow and Chevrolet's Turboglide also existed.

The Buick Dynaflow utilized the torque-multiplying characteristics of its planetary gearset in conjunction with the torque converter for low gear and bypassed the first turbine, using only the second turbine as vehicle speed increased.

The unavoidable trade-off with this arrangement was low efficiency and eventually these transmissions were discontinued in favor of the more efficient three speed units with a conventional three element torque converter.