[aligring]

Hi, I hope Im posting in the right area. I have a cc 1320, the other day i was riding it back to the shed when a high screech sound came out of no where and a hard jerk caused the engine to die. This happened extremely fast. Probably 1 second until the engine died.The engine wouldn't start, it felt like something was holding it. I took off the drive belt that connects from the engine to the tranny and the engine starts. So the engine is fine. The pully wheel on the tranny will not move, its rock solid. I assume the tranny is locked up. But the weird thing is that i can still roll the mower. when i engage the hydro dump valve, i can roll the mower and the rear wheels move just fine. Do u guys have any suggests. DO u think the tranny is gone or can something we done to fix it and allow that pully to move freely? Any help would be appreciated. Thanks