Help dropping lower unit

[nymack66]

I am assuming you absolutely sure all the bolts are removed, then it frozen on the upper splines place the boat in forward or reverse and grab the prop and rock it hard back and forth whilst a friend or help gently tap on the lower unit with a piece of wood and sledge hammer it will eventually drop please take your time and error on the side of patience.
Someone did not do a good job lubricating the shaft previously.