Thanks for the help. I talked to a buddy last night and he said sometimes that you have to have two men pulling up on it at the same time but it should release with enough vertical tension. I'm getting ready to give it another shot.
Update. Was able to get the pump out by attaching a ratchet strap to the chain right next to the plate and ran the ratchet strap up to some angle iron spanning the top of the basin. I ratcheted the strap as tight as I could then I pulled onto chain from side to side and it broke loose.
