RCK60B23BX gearbox issues

good deal, when you see the price of a gear-box you didn't do too bad

I was going to suggest checking the bottom bearing in the spindle housing before rebuild/re-installation. May have already done that. The bearing gets loose and that's all that supports that long shaft, it flops around and takes out the lower bearing in the box, and the seal, oil leaks out, destroys gears and the other two bearings.

Also you can remove the shaft assembly with the pulley on it without removing the pulley (for replacing the seal), easy, but still cant get the bearing out without taking the box apart.

I know you & the dealer aren't on good terms, but if one would ask why they want to replace the gearbox because of the broken bolt hole, here's why. If they were to "JB weld it" and throw it back together, and that JB breaks (and it will at some point), the dealer now has a good chance of having to buy that box + labor and perhaps the entire deck; and they'd still have a mad customer. That's IF the owner didn't take them to a courtroom somewhere with a two-bit greedy attorney, then plaster the name of the dealership all over social media, billboards, and other potentially slanderous avenues. That is a set of real concerns for any dealership, thus they've become sort of "parts changers", which effectively passes some of the liability onto the manufacturer of the part, in this case Kubota. Car dealers have been doing this for YEARS, and for good reason. I hate the practice but it's necessary in some cases.

Congratulations! You saved some major $$$!