Throttle Positions

Minimum Throttle: The least amount of throttle opening required for upshift.

Light Throttle: Approximately ¼ of the accelerator pedal.

Medium Throttle: Approximately ½ of the accelerator pedal travel.

Heavy Throttle: Approximately ¾ of the accelerator pedal travel.

Wide Open Throttle (WOT): Full travel of the accelerator pedal.

Full Throttle Detent Densified: A quick application of the accelerator pedal to its full travel in order to force a downshift.

Engine Braking: A condition in which you use the engine in order to slow the car by downshifting manually during a zero-throttle coastdown.

Zero Throttle Coastdown: A full release of the accelerator pedal while the car is in motion and in drive range.

Shift Conditions

Bump: A sudden and forceful engagement of a clutch or band.

Chuggle: A bucking or jerking that is most noticeable when the converter clutch is engaged. A Chuggle is similar to the feel of towing a trailer.

Delayed: A condition in which a shift is expected but does not occur for a period of time. Delayed is also defined as late or Extended.

Double Bump (Double Feel): Two sudden and forceful engagements of a clutch or a band.

Early: A condition in which the shift occurs before the car has reached the proper speed. The early condition tends to labor the engine after the upshift.

End Bump: A firmer feel at the end of a shift as compared to the feel at the start of the shift. End bump also is define as END FEEL or SLIP BUMP.

Firm: A noticeably quick engagement of a clutch or band that is considered normal with a medium to heavy throttle. This should not be confused with HARSH or ROUGH.

Flare: A quick increase in engine rpm along with a momentary loss of torque. This generally occurs during a shift. Flare is also defined as SLIPPING.

Harsh (Rough): A more noticeable engagement of a clutch or a band as compared with FIRM. This condition is considered undesirable at any throttle position.

Hunting: A repeating quick series of upshifts and downshifts that causes a noticeable change in engine rpm. An example is a 4-3-4 shift pattern. Hunting also is defined as BUSYNESS.

Initial Feel: A distinct sturdy feel at the start of a shift as compared to the end of the shift.

Late: A shift occurs when the engine is at a higher than normal rpm for a given amount of throttle.

Shudder: A continuous jerking condition similar to CHUGGLE but more severe and rapid. This condition is most noticeable during certain car speed ranges.

Slipping: A noticeable increase in engine rpm without a car speed increase. A slip usually occurs during or after the initial clutch or band engagement.

Soft: A slow, almost unnoticeable clutch or band engagement with very little shift feel.

Surge: A repeating acceleration and deceleration that is engine-related. This condition is less intense than CHUGGLE.

Tie Up: A condition in which two opposing clutches and/or bands are attempting to engage at the same time, causing the engine to labor with a noticeable loss of engine rpm.

Noise Conditions

Planetary Gear Noise: A whine related to the car speed that is most noticeable in the first gear or reverse. Planetary Gear Noise is less noticeable after an upshift.

Pump Noise: A high pitch whine that increases with engine rpm.

Abbreviations