Turbine Shaft
WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.
The turbine shaft is part of the direct/overdrive clutch assembly and is splined to the torque converter turbine. This allows input torque to be transmitted from the torque converter to the drive clutches and rear planetary carrier in reverse, 3rd, 4th, 5th and 6th gear and to the center sun gear and planetary in 1st and 2nd gears.