WARNING: This page is about a different car, the 2009 GMC Yukon and 2009 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Turbine Shaft O-Ring
Courtesy of GENERAL MOTORS CORP.
Install the O-ring (618) on the turbine shaft. O-Ring location is location dependent.