2009 250 HO.

Fished Friday 3 hours practiced for tourney, no issues engine preformed flawlessly. went out Saturday noticed it seemed a little more sluggish to plane out, but figured it might be the warmer humid morning, but it just felt a little different. Fish most of the day ran around tor 3 times. then on way back to ramp put it on plane still did not feel right, but got planed out and opened up at WOT to see if speed was same. Pretty close to my usual. so back off cruise about 4800 r's, 2 mins later acted like it jumped out of gear, will not go forward or reverse. Got towed back. Prop looks great, hub is undamaged. looked at case and see a marble size ping/bubble on port side case housing looked cracked from inside. Enguaged the shift lever and prop will spin freely by hand, both forward and reverse sounds like a sack of gravel in it. What happened inside???