I was driving my lucky car last night and all of a sudden the entire car started shaking.. I thought it was the transmission because the shift knob was vibrating so much you could hardly hold onto it. I pulled into a parking lot as soon as I could and noticed the car was leaking oil. By this time the engine sounded awful, clunking etc. My harmonic balancer came loose somehow and was free spinning on the crank. I have no idea how, but I am wondering what kind of damage it caused. If the front seal is leaking, am I going to need to pull engine or get a new small block?