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Ramp Angle

An angle formed by lines adjacent to the static-loaded radius of the front and rear wheels intersecting at the point of the lowest ground clearance under the middle of the vehicle.

Ramps

Transitions between voltage levels of sine waves that change at a constant rate.

Ranco Control

A tradename often used for a thermostat.

Random Access Memory (RAM)

A computer memory into which the user can enter information and instructions (write), and from which the user can call up data (read).

Random Intermittent Welds

Welds on one or both sides of a joint in which the weld increments are made without regard to spacing.

Range Shift Cylinder

Located in the auxiliary section of the transmission, this component, when directed by air pressure via low and high ports, shifts between high and low range of gears.

Range Shift Lever

Located on the shift knob, this lever allows the driver to select low- or high-gear range.

Rankine

A thermometer scale for which the freezing point of water is 492oR. Absolute zero is the beginning of this thermometer scale.

Rankine Scale

See Rankine.

RAP

1. Acronym for Remote Anti-Theft Personality Module (Ford) 2. Retained accessory power (GM).

Raster

A type of display were each pattern is stacked one on top of the other.

Raster Pattern

Also known a stacked pattern.

Rat

A Chevrolet big block V-8 engine.

Rat Motor

A nickname for any engine from the Chevy V8 (Big-Block) family. Originally released in 1965 as a 396 cid and available today with displacements as high as 572 cid with 720 BHP.

Ratch

The minimum sensed TP voltage standard.

Ratio

1. The relative amounts of two or more substances in a mixture. 2. The comparison of two numbers as in teeth on gears.

Ratio Valve

A device used on the front or steering axle of a heavy-duty vehicle to limit the brake application pressure to the actuators during normal service braking.

Rationality

A term associated with comprehensive component testing in which signal inputs from components are compared to inputs from other components to verify conditions coincide.

Ravigneaux Gear Train

A planetary gear train with two sun gears, three long and three short planetary pinions, planetary carrier, and ring gear.

Raytech

Manufacturer of test equipment such as infrared thermocouples.