I'm lost....who's the Honda model # expert?

I have a mower that's got some transmission issues, and I'm starting to look at parts prices online. I'm not getting very far though, since my model number isn't listed anywhere, even on the Honda website. The numbers are...

Model: HRX2172HXA
Serial No: MAGA-2011018

I can get close, but not exact with the model number, and even then my serial number throws it all off. My options on the Honda page that are close are....

HRX217 HXA MAGA-1000001-1299999
HRX217K1HXA MAGA-1400001-1499999

The other 16 options start to get farther away from the numbers I've got on my tag. Do I have some oddball mower that parts aren't available for any more?

Any thoughts appreciated.

I'm lost....who's the Honda model # expert?