At a glance
What can fail
On certain vehicles with 3.0L and 3.8L engines, corrosion can damage the rear lower mount retaining plates, causing the subframe body mounts to detach at the rear corners. This allows the subframe to drop, which can make steering very difficult and reduce vehicle control.
What the fix does
Modified lower body mounts and attaching bolts will be installed to secure the subframe properly.
Summarized — see the official notice for exact wording, dates, and contacts.