Automatic Transmission – 4L60E – General Information Page 7C1–11
4 Transmission Definitions and
Abbreviations
The following definitions and abbreviations are provided to establish a common language and assist the user in
describing transmission related conditions. The use of these terms and/or conditions can be found in the various parts of
the automatic transmission sections, but more particularly in 7C3 Automatic Transmission – 4L60E – Hydraulic and
Mechanical Diagnosis.
4.1 Throttle Position Related Definitions
Throttle Position Definition
Minimum Throttle The least amount of throttle opening required for an upshift.
Light Throttle Approximately 1/4 of accelerator pedal travel (25% Throttle Position).
Medium Throttle Approximately 1/2 of accelerator pedal travel (50% Throttle Position).
Heavy Throttle Approximately 3/4 of accelerator pedal travel (75% Throttle Position).
Wide Open Throttle (WOT) Full travel of the accelerator pedal (100% Throttle Position).
Full Throttle Detent Downshift A quick apply of the accelerator pedal to its full travel, forcing a downshift.
Zero Throttle Coast Down A full release of the accelerator pedal while the car is in motion and in drive range.
Engine Braking A condition where the engine is used to slow the car by manually downshifting
during a zero throttle coast down.
4.2 Noise Condition Related Definitions
Noise Condition Definition
Planetary Gear Noise A whine related to car speed most noticeable in first gear or reverse. Becomes less
noticeable after an upshift.
Pump Noise A high pitch whine increasing with engine r.p.m.
4.3 General Definitions
General Definition
Accumulator A component of the transmission that absorbs hydraulic pressure during the apply of a
clutch or band. Accumulators are designed to control the quality of a shift from one gear range to another.
Adaptive Learning Programming within the TCM that automatically adjusts hydraulic pressures in order to compensate for changes in the transmission (i.e. component wear).
Applied An 'Applied Component' is holding another component to which it is splined or
assembled to. Also referred to as "engaged".
Apply Components Hydraulically operated clutches, servo’s, bands and mechanical one-way roller or
sprag clutches that drive or hold members of a planetary gear set.
Apply Plate A steel clutch plate in a clutch pack, located next to the (apply) piston.
Backing Plate A steel plate in a clutch pack that is usually the last plate in that clutch assembly
(furthest from the clutch piston).
Band An apply component that consists of a flexible strip of steel and friction material that
wraps around a drum. When applied, it tightens around the drum and prevents the drum from rotating.
Brake Switch An electrical device that provides signals to the transmission control module (TCM),
based on the position of the brake pedal. The TCM uses this information to apply or
release the torque converter clutch (TCC).
Centrifugal Force A force that is imparted on an object (due to rotation) that increases as that object moves further away from a centre-point of rotation.
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ISUZU KB P190 2007
