all belts are on, checked the wheels keys are in.it is a rhdro trans, the book says its sealed from factory, no where to put any in,ok, did you check the belts to make sure they are not missing, off the pulleys or broken?
maybe the clutch is rusted or otherwise stuck, mkesure the levers are moving freely with the pedal.
without looking up the actual mower I think it is a hydrostatic trans, was there "oil" leaking from the trans, maybe it needs transfluid...
doubting this one, but saw it once, both keys on both axles broke and the axle spun inside the rims, make sure that isn't happening..
here's a link to the parts and troubleshooting for the mower...
Craftsman 917288563 front-engine lawn tractor parts | Sears PartsDirect
Craftsman 917288563 front-engine lawn tractor parts - manufacturer-approved parts for a proper fit every time! We also have installation guides, diagrams and manuals to help you along the way!www.searspartsdirect.com
pulled the motor and scraped it.can you turn the transmission pulley by hand? or is it locked?
If you can turn it by hand does the axle move at all.
ALso do the wheels spin free in otherwords do they turn if you push the mower? If they do then the rod in the back is in the out position diengaging the axle from the transmission. On my dyt4000 this happened once, we had to grease it up and force it in, then all was fine.
Putting my dyt4000 with the rear wheels off the ground and putting it in gear one wheel spins forward the other spins in reverse, just like a car does... Put some resistance and both spin forward when in forward geer.. if you hand spin the also spin opposite.. (had to try it and this is how it works).
other then those things looks like a bad trans, I believe tyrel dactyle has a video showing how to rebild them..