Glossary “planetary pinion gears” Definition:
Small gears fitted into a framework called the planetary carrier.

Glossary “planetary gear train” Definition:
Gears of the transmission in either the Simpson or Ravigneaux design.

Glossary “planetary carrier” Definition:
The framework holding the planetary pinions within the sun gear.

Glossary “planetary gear set” Definition:
A group of gears named after the solar system because of their arrangement and action. This unit consists of a center (sun) gear around which the pinion (planet) gears revolve. The assembly is placed inside a ring gear having internal teeth. All gears mesh constantly. Planetary gear sets may be used to increase or decrease torque and/or obtain neutral, low, intermediate, high, or reverse.

Glossary “planetary gear system” Definition:
A gear set consisting of a central sun gear surrounded by two or more planet gears which are, in turn, meshed with a ring gear, used in overdrives and automatic transmissions.