Loud cranking noises coming from under the hood, could it be the transmission?

What is your question?

When I turn on the car it makes "loud" cranking noises also makes the car shake and the rpm indicator on the dash board starts to slowly go down( haven't let it run for more then 10 seconds in fear of causing further damage) . I haven't taken it in for inspection yet so I'm not sure what it is. Any suggestions would be greatly appreciated.