Recently replaced transmissions and after doing so i have developed this strange clanking/knocking noise that seems to be coming from the motor...but just doesn't make any sense. I pulled the motor to do a balance shaft eliminate, replaced timing belt/pulleys/etc. Then decided to swap trannys while i was at it. When i get everything put back into car i get this strange clanking noise. I haven't been driving the car do to this issue. You don't even have to have the motor running to hear the noise, if you bump the starter you can hear it. Also something strange, if you take all the spark plugs out the sound goes away....but put just one back in and it doesn't matter which cylinder...the sound is back....Have good oil pressure, rod bearings are new (replaced those after developing the sound...didn't help)....any suggestions? I was starting to lean towards maybe a flywheel issue?