General Description - Transaxle Definitions

The following definitions establish a common language and assist the user in describing transmission related conditions. Some of these terms or conditions are used in the transmission diagnosis sections.

THROTTLE POSITIONS
^ Engine Braking - a condition where the engine is used to slow the vehicle by manually downshifting during a zero throttle coastdown.
^ Full Throttle Detent Downshift - a quick apply of the accelerator pedal to its full travel, forcing a downshift.
^ Heavy Throttle - approximately 3/4 of the accelerator pedal travel.
^ Light Throttle - approximately 1/4 of the accelerator pedal travel.
^ Medium Throttle - approximately 1/2 of the accelerator pedal travel.
^ Minimum Throttle - the least amount of throttle opening required for an upshift.
^ Wide Open Throttle (WOT) - full travel of the accelerator pedal.
^ Zero Throttle Coastdown - a full release of the accelerator pedal while the vehicle is in motion and in drive range.

SHIFT CONDITIONS
^ Bump - a sudden and forceful apply of a clutch or band.
^ Chuggle - a bucking or jerking condition that may be engine related. It may be most noticeable when the converter clutch is engaged. Similar to the feel of towing a trailer.
^ Delayed - a condition where a shift is expected but does not occur for a period of time. Samples of this condition could be described as clutch or band engagement does not occur as quickly as expected during a part throttle or wide open throttle apply of the accelerator or when manually downshifting to a lower range, also as LATE or EXTENDED.
^ Double Bump or Double Feel - two sudden and forceful applies of a clutch or band.
^ Early - a condition where the shift occurs before the vehicle has reached a proper speed and 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. Also defined as END FEEL or SLIP BUMP.
^ Firm - a noticeable quick apply of a clutch or band that is considered normal with a medium to heavy throttle shift. It should not be confused with HARSH or ROUGH.
^ Flare - a quick increase in engine RPM accompanied with a momentary loss of torque. This most generally occurs during a shift, also defined as SLIPPING.
^ Harsh Rough - a more noticeable apply of a clutch or band as compared to FIRM. This condition is considered undesirable at any throttle position.
^ Hunting - a quick repeating series of upshifts and downshifts that cause a noticeable change in engine speed. An example could be described as a 4-3-4 shift pattern. Also defined a busyness.
^ Initial Feed - a distinct firmer feel at the start of a shift as compared to the finish of the shift.
^ Late - a shift that occurs when the engine is at a higher than normal RPM for a given amount of throttle.
^ Shudder - a repeating jerking sensation similar to CHUGGLE but more severe and rapid in nature. This condition may be most noticeable during certain ranges of vehicle speed. May also be used to define the condition during or after converter clutch engagement. Slipping - a noticeable increase in engine RPM without a vehicle speed increase. A slip usually occurs during or after initial clutch or band engagement.
^ Soft - a slow, almost unnoticeable clutch apply with very little shift feel.
^ Surge - a repeating engine related feeling of acceleration and deceleration that is less intense than CHUGGLE.
^ Tie-Up - A condition where two opposing clutches are attempting to apply at the same time causing the engine to labor with a noticeable loss of engine RPM.

NOISE CONDITIONS
^ Drive Link Noise - a whine or growl that increases and fades with vehicle speed and is most noticeable under light throttle acceleration. May also be noticeable in Park or NEUTRAL operating ranges with the vehicle stationary.
^ Final Drive Noise - a hum related to vehicle speed which is most noticeable under light throttle acceleration.
^ Gear Noise - a whine, most noticeable in first gear and reverse that is related to vehicle speed. A gear noise condition may become less noticeable or go away after an upshift.
^ Pump Noise - a high pitch whine that increases in intensity with engine RPM. This condition may also be noticeable in all operating ranges with the vehicle stationary or moving.