Had trans rebuilt thursday c6 he put a small stall in it, had to cut exhaust off in order to take trans in and out.I drove truck about 10 miles to muffler shop to put exhaust on they said sounded like i had a lifter knocking torque con. hitting something today driving heard something like a hammer hitting the engine towing company said bent push rod what could of caused this. Any info appreciated

 

I know I talked about this a wile ago. Remove the valve covers and see if ya got a bent rod. It will be easy to spot. Could also be Fly wheel Flex Plate or converter

 

I agree,check the flex plate.Sometimes the center hole in the flex plate is tight on the torque converter,causing it to deform.It also might just be a cracked flex plate.Thay both make the engine sound like it has a knock in it.