Hey BiggDogg
The usual signs are mostly visual...
when the rubber piece look like yours, it needs to be replaced...
Loose steering, grabby steering (like it grabs and releases)...
Worse case scenero, it will completely let go on ya...
I'm not exactly sure why Ford used that technology unless it was intended to dampen some of the road vibrations.
I think the U-joint style coupler works much better...
KaptnKA

S