WARNING: This page is about a different car, the 2004 Mercury Mountaineer and 2004 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
On 4x2 vehicles, use the special tool to install the extension housing seal.
Fig 1: Installing Extension Housing Seal
Courtesy of FORD MOTOR CO.
On 4x4 vehicles, use the special tool to install the extension housing seal.