Try driving out the large roll pin, then drive 2 large screwdrivers between the coupler and steering box, like you're trying to separate them. If is the telescoping type, it will push in towards the firewall. If you have the column out, stand it up on the floor on the steering wheel, and tap it down with a 2x4.
There are some columns that DON"T collapse. Most of the ones that I've owned did (around 10), one didn't.
Rob