Terms, Abbreviations and Acronyms

GENERAL INFORMATION.

The following describes some terms, abbreviations and acronyms related to the

design and operation of the automatic transmission..

Throttle Positions (TP).

• Minimum throttle opening – corresponds to the throttle opening angle required for the transmission to shift to the next higher gear..

• Light throttle opening – approximately corresponds to 1/4 accelerator pedal travel (25 percent throttle opening)..

• Medium throttle opening – approximately corresponds to 1/2 accelerator pedal travel (50.

percent throttle opening)..

• Heavy throttle opening – approximately corresponds to 3/4 accelerator pedal travel (75.

percent throttle opening)..

• Wide-open throttle – corresponds to full accelerator pedal travel (100.

percent throttle opening)..

• Downshift at wide-open throttle – rapid and full depression of the

accelerator pedal, causing the transmission to shift to the next lower gear..

• Coasting – vehicle movement with a gear engaged and the throttle fully closed (accelerator pedal released)..

• Engine braking – vehicle movement with the throttle fully closed in a gear

manually selected lower gear.

Characteristic shift quality conditions.

• Flare – a noticeable increase in engine speed not accompanied by a

corresponding increase in vehicle speed. Slipping of friction elements

occurs during the initial phase of the shift..

• Wavy shift – accompanied by slight longitudinal vehicle accelerations..

• Double bump – abrupt and strong engagement of a clutch or band brake of the

transmission..

• Harsh shift – noticeable rapid engagement of friction elements.

transmission case..

• Delayed engagement – delay in gear engagement. May occur due to a delayed engagement of a clutch or band brake with the throttle partially or fully open

or after manually selecting the lower transmission range..

• Final bump – occurs in the final phase of the shift due to

abrupt full engagement or seizure of friction elements..

• Smooth shift – almost imperceptible, very smooth transmission shifting.

transmission..

• Initial bump – occurs in the first phase of the shift due to abrupt initial engagement or seizure of friction elements..

• Early shift – premature gear shift (before the vehicle reaches the speed corresponding to shifting to the next gear). Causes

engine overload when shifting to the next higher gear..

• Overlap shift – premature engagement of the friction element of the next gear or delayed release of the friction element of the previous gear. Heavy overlap causes intensive

slipping of friction elements under load, increased load and engine speed drop..

• Late shift – gear shift occurs only after the vehicle has significantly exceeded the speed corresponding to shifting to the next

gear. Accompanied by increased engine speed and noise..

• Power flow interruption, friction element slipping – accompanied by a

brief, sharp increase in engine speed due to load removal during the shift..

• Hard shift – stronger than a "harsh" shift, engagement of friction elements. Hard shifting is undesirable at any degree of

throttle opening..

• Shudder – gear shift accompanied by brief longitudinal

vehicle accelerations and decelerations similar to those that may

be felt when towing a trailer. Sensitivity to shudder increases when the torque converter clutch is locked..

• Judder – repeated intense longitudinal jerks similar to those described under "Shudder", but stronger and faster. Judder usually occurs within a

certain vehicle speed range..

• Bump – abrupt and strong engagement of a clutch or band brake of the transmission.

transmission..

• Cyclic shifting – a chain of rapid, brief shifts between adjacent transmission gears, for example, 4–3–4th... gears. Cyclic shifting

is accompanied by a significant change in engine speed.

Abbreviations:.

PRB (PSA) – Pressure relay block.

TCM (TCM) – Transmission control module.

ISS (AS) – Input shaft speed sensor.

TPS (TPS) – Throttle position sensor.

VSS (VSS) – Vehicle speed sensor.

CTS (CTS) – Engine coolant temperature sensor.

TFT (TTS) – Transmission fluid temperature sensor.

NC (NC) – Normally closed.

NO (NO) – Normally open.

TCC (TCC) – Torque converter clutch.

PWM (PWM) – Pulse width modulation.

PCS (PCS) – Pressure control solenoid.