Has your transmission ever broke in half?

[Adam12]

Today I went to show my brother that we finaly got my truck running a few weeks ago. I cant go anywhere because I have no driveline but it fires up fine and runs sweet. its a 454 block bored to 481 with a th-400 trans today i fired it up and reved it up a lil then I felt the pedal give and heard the sound of metal falling on the cement. I get out and look under the hood and the motor was sagging bad in the back, so I look under and see that my transmission is nearly upside down! the bell housing on the transmission just broke somehow and chucks of metal were on the ground and tranny fluid was everywhere. anyone know what may have caused this? could it be because there was no driveline installed? oh yeah it ripped the trans mount all up too. I asked around and no one I have talked to has ever seen anything like this.