WARNING: This page is about a different car, the 2003 Mercury Marauder, 2003 Mercury Grand Marquis, and 2003 Ford Crown Victoria. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Installing Band - Low And Reverse Components
Courtesy of FORD MOTOR CO.
The low and reverse band holds the pinion carrier in reverse. The reverse band also applies in manual 1 position to provide engine braking.