It is costly enough to replace those transmissions. If it comes down to paying labor to do it, most don't. Sounds like some troubleshooting is in order.

Might be worth hanging on to and trying to find a transmission.

There's a guy on local CL that has been trying to sell his for parts for quite a while, so they are out there. I too have one that might work (too bad you aren't close).

Might float a WTB on CL and see if you get any bites.

thanks for your replies. The strange part about this is that the mower was running fine and after cutting one day and putting it away, the next time I used it (4-5 days later), the trans was not working. No symptoms of trans failure. No grinding or popping or squealing noises. Possibly the cable or cable connector?

Possibly. You may want to get some hands on to see really what the issue is. Or to a repair shop that can do the same.