The present invention relates to a method and apparatus to prevent clutch slip for a hybrid prowertrain system. A powertrain for controlling an electro-mechanical transmission mechanically-operativelycoupled to an engine and an electric machine adapted to selectively transmit mechanical power to an output member through selective application of a plurality of torque-transfer clutches includes monitoring a clutch slip speed, synchronizing an oncoming clutch, and constraining reactive clutch torque limits for the oncoming clutch to achieve a reactive clutch torque that is less than an estimatedclutch torque capacity.