Glossary “gear roll over” Definition:
Noise that can be heard with the transmission in neutral and the engine idling. It is caused by the speeding up and slowing down of the crankshaft at idle. This causes the gears to impact one another, causing a rapping noise, this is a normal condition.

Glossary “gear rotor pump” Definition:
Type of pump that uses rotor gears to move liquid.

Glossary “gear shift” Definition:
1). A floor or steering colume mounted lever used to manually change gears in the transmission. 2). Linkage type mechanism by which the gears in a transmission are engaged.

Glossary “gear tooth pattern” Definition:
With the use of gear marking compound, the gear tooth patterns will appear as marking on both the drive and coast sides of the ring gear tooth. Patterns can be describes as being high or low (deep) and towards the heel or the toe.

Glossary “gear type pump” Definition:
Pump that uses two rotating gears to draw in fluid that is carried around the outer pump body in cavities between gear teeth and dispensed under pressure as the gear mesh together.

Glossary “gear whine” Definition:
A high pitched sound developed by some types of meshing gears.

Glossary “gear rattle” Definition:
A repetitive metallic impact or rapping noise that occurs when the vehicle is lugging in gear. The intensity of the noise increases with operating temperature and engine torque, and decreases with increasing vehicle speed.

Glossary “gear reduction” Definition:
Condition in which the drive gear rotates faster than the driven gear. Output speeds of the driven gear is reduced, while output torque is increased.

Glossary “gear pitch” Definition:
The number of teeth in a given unit of pitch diameter.

Glossary “gear pump” Definition:
Positive displacement pump that uses an inner drive gear and an outer driven gear, separated on one side by a crescent, to produce oil flow. Gear pumps may use either helical or spur gears and are sometimes called gear-and-crescent pumps.

Glossary “gear radius” Definition:
Distance from the center of a gear to its outside edge. It is where the torque is measured from.

Glossary “gear ratio” Definition:
1). The speed relationship that exists between a driving (input) and a driven (output) gear. For example, a driving gear that revolves twice for each driven gear revolution has a 2 to 1 (2:1) ratio. 2). The number of turns, or revolutions, made by the drive gear compared to the number of turns made by the driven gear.

Glossary “gear pattern” Definition:
Pattern taken off of the ring gear teeth from a coating of colored paste applied to the gear teeth. Shows the contact areas of the ring ring and pinion.

Glossary “gear drive” Definition:
System of two or more gears, such as one that transmits power from the crankshaft or camshaft.

Glossary “gear lubricant” Definition:
Type of oil or grease especially formulated to lubricate gears.

Glossary “gear noise” Definition:
The howling or whining of the ring gear and pinion due to an improper gear set pattern, gear damage, or improper bearing preload.

Glossary “gear oil” Definition:
A thick lubricant, generally with an SAE number of 80 or above, used in standard transmissions or differentials. These often contain additives, such as an EP additive, to guard against being squeezed out from between gear teeth.

Glossary “gear oil limited-slip” Definition:
Lubricant specified for use in certain limited slip differentials to prevent chattering during turns and/or abnormal wear to the parts.

Glossary “gear backlash” Definition:
Measurable gap or slack between gears.