Page 202 - Hydra-matic 6 Speed RWD Technician's Guide (October 2005)

GLOSSARY OF TECHNICAL TERMS

Adaptive Learning: Programming within the TCM De-energize(d): To interrupt the electrical current that
that automatically adjusts hydraulic pressures in order flows to an electronically controlled device making it
to compensate for changes in the transmission (i.e. electrically inoperable.
component wear).
Downshift: A change in a gear ratio where input
Applied: An apply component that is holding another speed and torque increases.
component to which it is splined or assembled with. Driver Shift Control: A selector system variant which
Also referred to as “engaged”.
is configured to be shifted only manually, and allows for
Apply Components: Hydraulically operated clutches, engine braking in first, second, third and fourth gears.
servos, bands, and mechanical one-way roller or sprag Duty Cycle: In reference to an electronically controlled
clutches that drive or hold members of a planetary solenoid, it is the amount of time (expressed as a
gear set. percentage) that current flows through the solenoid coil.
Apply Plate: A steel clutch plate in a clutch pack Engine Control Module (ECM): An electronic device
located next to the (apply) piston. that manages the electrical system of the engine.
Backing Plate: A steel plate in a clutch pack that is Energize(d): To supply a current to an electronically
usually the last plate in that clutch assembly (farthest controlled device enabling it to perform its designed
from the clutch piston). function.
Ball Check Valve: A spherical hydraulically controlled Engine Compression Braking: A condition where
component (made of steel or plastic) that either seals compression from the engine is used with the
or opens fluid circuits. It is also referred to as a check transmission to decrease vehicle speed. Braking
valve or checkball. (slowing of the vehicle) occurs when a lower gear ratio
is manually selected by moving the gear selector lever.
Brake Switch: An electrical device that provides
signals to the Transmission Control Module (TCM) Exhaust: The release of fluid pressure from a hydraulic
based on the position of the brake pedal. The TCM circuit. (The words exhausts and exhausting are also
uses this information to apply or release the torque used and have the same intended meaning.)
converter clutch (TCC). Fluid: Generally considered a liquid or gas. In this
publication fluid refers primarily to “transmission fluid”.
Centrifugal Force: A force that is imparted on an
object (due to rotation) that increases as that object Fluid Pressure: A pressure (in this textbook usually
moves further away from a center/point of rotation. transmission fluid) that is consistent throughout its circuit.
Clutch Pack: An assembly of components generally Force: A measurable effort that is exerted on an object
consisting of clutch plates, an apply plate and a (component).
backing plate.
Freewheeling: A condition where power is lost through
Clutch Plate: A hydraulically activated component a driving or holding device (i.e. roller or sprag clutches).
that has two basic designs: (1) all steel, or (2) a steel Friction Material: A heat and wear resistant fibrous
core with friction material bonded to one or two sides material bonded to clutch plates and bands.
of the plate.
Gear: A round, toothed device that is used for
Compensator: A component of the transmission that transmitting torque through other components.
absorbs hydraulic pressure during the apply of a clutch.
Controlled in the circuit with a regulator valve. Gear Range: A specific speed to torque ratio at
which the transmission is operating (i.e. 1st gear,
Component: Any physical part of the transmission. 2nd gear etc.).

Control Valve Body: A machined metal casting that Gear Ratio: Revolutions of an input gear as compared
contains valve trains and other hydraulically controlled to the revolutions of an output gear. It can also be
components that shift the transmission. expressed as the number of teeth on a gear as compared
to the number of teeth on a gear that it is in mesh with.
Coupling Speed: The speed at which a vehicle is
traveling and no longer requires torque multiplication Hydraulic Circuit: A fluid passage which often
through the torque converter. At this point the stator includes the mechanical components in that circuit
free wheels to allow fluid leaving the turbine to flow designed to perform a specific function.
directly to the pump. (See torque converter)

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