79 ford c6 tranny problem (auto)?

I replaced the tranny on my truck with another c6 and I got the transmission put up in the truck and got everything bolted down. But when it s time to crank over the truck, while it s cranking you can hear this noise that sounds like either the flywheel or the dust guard. But when the truck finally fires up the noise is louder and scary… And my motor shakes from hell but the tranny doesn t… What could be the problem? Is the tranny jammed? Or is something not right? What am I missing?

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