Operation CHARM: Car repair manuals for everyone.

Shift Conditions

Bump - a sudden and forceful application of the clutch or the band.

Chuggle - a bucking or jerking condition that may be engine related. Chuggling may be most noticeable when the torque converter clutch is engaged, and may feel similar to the feel of towing a trailer.

Delayed - a condition where a shift is expected but is delayed. Some samples of this condition could be described as clutch or band engagement that does not occur as quickly as expected during part throttle, wide open throttle, or engine braking. Also described as LATE or EXTENDED.

Double Bump - two sudden and forceful application of clutch or the band. Also defined as double feel.

Early - a condition where a shift occurs before the vehicle has reached the proper speed and tends to labor the engine after upshift.

End Bump - the 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 application of the clutch or the band that is considered normal with a medium to heavy throttle shift. Should not be confused with HARSH or "rough."

Flare - a quick increase in engine RPM accompanied by momentary torque loss. This generally occurs during a shift. Also defined as SLIPPING.

Harsh - a more noticeable application of the clutch or the band as compared to FIRM. This condition is considered undesirable at any throttle position. Also referred to as "rough.,

Hunting - a repeating quick series of upshifts and downshifts causing a noticeable change in engine RPM. An example could be described as a 4-3-4 shift pattern. Also defined as Busyness.

Initial Feel - the 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 higher than normal RPM for a given amount of throttle.

Shudder - a repeating jerking sensation similar to a 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 after torque converter clutch engagement.

Slipping - a noticeable increase in engine RPM without an increase in vehicle speed. The slip usually occurs during or after the initial clutch or band apply.

Soft - slow and 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 noticeable loss of engine RPM.