An apparatus is disclosed which is mountable in a strapping machine frame adjacent a strap chute and adjacent a strap end gripping and sealing assembly. The apparatus has a pivotably mounted strap guide arm and gripper for guiding the strap during feeding in a first, upper position and for gripping the strap when the arm moves downwardly away from the first position. The strap is both fed into the strap chute and subsequently pre-tensioned by a pair of coacting feedwheels. A high tension pinion gear is mounted for rotation on an axis which is fixed relative to, and movable with, the strap guide arm. The pinion gear engages a rack member which is secured on one end to the strapping machine frame and which transmits the reaction force from the pinion gear to the strapping machine frame when the pinion gear is rotated in engagement with the rack. A single, reversible, rotating drive motor is mounted for movement with the guide arm and powers a gear drive assembly which is engaged with the motor and movable therewith for (1) rotating the feedwheels to feed the strap when the motor is rotating in a first direction, (2) rotating the feedwheels to withdraw the strap to pretension the loop with a first predetermined tension when the motor is rotating in a second direction, and (3) rotating the high tension pinion gear when both (a) the motor is rotating in the second direction and (b) the tension in the strap exceeds the predetermined, first tension. During high tensioning, the pinion gear moves along the rack and pivots the guide arm out of the first position to a second position whereby the gripper is actuated to grip the trailing portion of the strap and pull the gripped strap, thereby drawing a higher, second tension in the loop.