Which gear set name is associated with originally three speeds and later possible overdrive with minor modification?

Which gear set name is associated with originally three speeds and later possible overdrive with minor modification?

• A. ZF
• B. Ravigneaux
• C. Wilson
• D. Simpson

Answer: (B)

The concept being tested is how epicyclic (planetary) gear sets in automatics deliver multiple forward speeds and how a particular design lends itself to adding an overdrive stage with only small changes. In a planetary gear arrangement, you get different gear ratios by choosing which element is held, which is driven, and which provides output. The Ravigneaux gear set is a compact, compound epicyclic design that was widely used to provide three forward speeds in early automatics. Its arrangement is especially adaptable: with a minor modification—adding or reconfiguring a simple stage for another ratio—you can introduce an overdrive, giving a fourth forward speed without a complete redesign. That historical flexibility is why this gear set is associated with starting from three speeds and later enabling overdrive. The other gear-set families mentioned are not tied to that exact progression in the same way.

The concept being tested is how epicyclic (planetary) gear sets in automatics deliver multiple forward speeds and how a particular design lends itself to adding an overdrive stage with only small changes. In a planetary gear arrangement, you get different gear ratios by choosing which element is held, which is driven, and which provides output. The Ravigneaux gear set is a compact, compound epicyclic design that was widely used to provide three forward speeds in early automatics. Its arrangement is especially adaptable: with a minor modification—adding or reconfiguring a simple stage for another ratio—you can introduce an overdrive, giving a fourth forward speed without a complete redesign. That historical flexibility is why this gear set is associated with starting from three speeds and later enabling overdrive. The other gear-set families mentioned are not tied to that exact progression in the same way.