Have question for jdseller and others concerning my brothers jd 4630. He was hauling manure with tractor with smaller spreader (not working tractor hard). Came in for another load shut tractor off went to restart and flywheel would turn but engine is not. Split tractor and flywheel bolts are sheared off engine can be turned with wrench on front pulley. He has bolts out of crank and pin out of crank but there is some small grooves in flywheel where it mounts to crank. Should he machine this smooth again or get a different flywheel? I know this was an issue on 4630s Any suggestion as what needs to be done. It is mid production 4630 quad range not turned up or worked real hard any more. plans on keeping and using tractor.I can be reached at [email protected] thanks