Gm Global Technolgoy Operations, Inc.

Sheryl Page

Marek L Wilmanowicz

David Morganroth

Paul Skupinski

An improved powertrain control minimizes output torque disturbances due to garage shifting. Under certain predefined conditions, garage shifts to the forward or Drive range are carried out by initially commanding a shift to an upper forward gear ratio having a relatively low torque advantage, and then commanding a shift from the upper forward gear ratio to a lower forward ratio that is ordinarily used to launch the vehicle. The shift from the upper gear ratio to the lower gear ratio is initiated when the initial shift is substantially complete or when a predetermined period of time has elapsed since shift initiation. Engine management controls are also used to reduce the transmission input torque during garage shifts to both forward and reverse ranges.

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Ann Arbor, MI, United States of America

Sheryl Page