Setting out in the sun and mirror fell off. I removed the old glue, or what ever it was. I now need to know to remove the metal peice from the rest of the mirror. I can't find a simple way to do this.. I am afraid to do any prying for fear of breaking the plastic or what ever material it is.

On another truck, on the mirror there was a allen head set screw to loosen then the metal peice would come out.. I can't see anything like that on this truck..

 

There should be a slot at the bottom for a screwdriver to release pressure on the spring

 

Old thread...
Just bought rusty 99 with 80k that rear view was sitting on dash with pad attached.
I pried up a little through slot from below just enough so pad was over lip of mirror mount and slid it off.
My concern is that this did not slide off easily like all my GM models do, that the pad will pull free just hanging the mirror back onto windshield.
The kits for gluing this back onto glass is far different than what used to, just hung one 2 years ago and Permatex has what they deem as Ford TA-17-A Permanent Bond Adhesive.
Just a small blister package with tiny bag of adhesive n some cleaning pads inside. Previously you would get enough in a tube to do 2 of these, now 1 use packet style.
Says we can mount in 30m, guess will see if this style packet will be tough enough to mount a Ford rear view mirror.
My issue is getting the old glue off, looks like they used an adhesive badge as it is thick and uniform, no women here so no nail polish remover, although they do not appear to make the same product we were used to seeing the women use back in the day and may not have worked like it did on even super glue. So soaking in pure Isopropyl and crossing fingers it will come off...

 

After 15 minutes of soaking that pad was pliable enough could start to pull free at one corner then grabbed with needle nosed pliers and removed the factory glue, in case others were having trouble removing that pad, it was about 1/32" thick.
Pad is hung, but think will give it more than the 30M they say is adequate, will hang mirror in AM...

 

On my 99 XLT there was slot there, but spring is on the sides, you just pry enough to clear mirror and slide downwards when in your hands, you would slide upwards if still attached to windshield as mirror slides down over the mounting pad.
There was no spring underneath the pad in my instance...

 

Glad to hear you got it back on.