68 F250, starter engaging flywheel, then nothing...

[Kat777]

as the title says, i stopped to pick up a friend yesterday, and when i tried to start Wimbleton to head out, i got noise from the starter and heard the flywheel kick, but thats all I've got. Not so much as a single pulley turning, and nothing moving that i can see through the oil filler. same result from jumping the solenoid.  My first thought is a broken timing chain, but unfortunately before my dad passed i didn't get a chance to learn much more than accessory engine components (starter, alternator, pumps, etc.) and I'm hearing all sorts of other theories from friends. any suggestions on what to check? He's about a mile from our house, so id like to have a few thing to look for before i walk down there!  

[Ranchero50]

Most likely your starter is buggered internally.