Don't pry the drive off. You'll wind up cracking the housing or worse. Sounds like your coupler let go. You;ll need to get back in there and cut the input shaft that goes into the coupler. Not easy but not uncomon. Of course t will also need to be replaced. I found that a sawzall works best and I used the long blades with the grit teeth that are used for cutting cast iron soil pipes work best. Regular blades won't cut that hardened shaft. A cut off wheel would work great but usually not enough room back there.

Did get the drive off. Took a peek under the top cap. Looks like I am missing a few teeth from the bottom horizontal gear. Metal chips here and there.

So do I rebuild or get a new one? Does the newer style XR bolt up with out changing out anything else?
changing anything else?