Overlap Shifting

During the transition of overlap, the clutches run through a slip zone. The torque is gradually transferred from the clutch that is releasing to the clutch that is engaging.

Fig 1: Identifying Overlap Shifting (Clutch 1 Partially Engaged And Clutch 2 Partially Disengaged)

Courtesy of BMW OF NORTH AMERICA, INC.

The new gear engages the moment the torque level exceeds that of the first clutch. This is described as overlap. If the overlap is correct, (zero overlap) the engaging clutch takes over as much torque as the disengaging clutch releases. The result is a seemingly unnoticed shift of the best quality.

Fig 2: Identifying Overlap Shifting (Clutch 1 Disengaged And Clutch 2 Fully Engaged)

Courtesy of BMW OF NORTH AMERICA, INC.