Patent ID: 8712651

Claim:
A method of shifting a multi-mode drive unit comprising a transmission, a power take off unit having a first plurality of gear ratios and coupled to said transmission, and a rear drive module having a second plurality of gear ratios and coupled to said power take off unit, wherein said method in response to a shift request comprises: initiating a shift in said power take off unit from operation in a first gear ratio of said first plurality of gear ratios to operation in a second gear ratio of said first plurality of gear ratios; monitoring the progress of said shift of said power take off unit; rejecting said shift request if said power take off unit is unable to successfully shift from operation in said first gear ratio of said first plurality of gear ratios to operation in said second gear ratio of said first plurality of gear ratios; and shifting said rear drive module from operation in a first gear ratio of said second plurality of gear ratios to operation in a second gear ratio of said second plurality of gear ratios if said shift of said power take off unit is successfully completed.