Steering column to steering box problems

I know I'm late to the conversation, but I had the same problem with my E Body. I called "Cardone" the company that I bought the rebuilt steering box from.
I was told that it would not hurt the box if you drive the coupler on with reasonable strikes with a hammer.
I did, (make sure you have lined up the spline correctly and use a brass hammer or something to keep fron damaging the coupler) I drove it on with a few light taps, pulled it of, then repeated a few times until it was fully inserted. Then connected the columm shaft to the coupler. This was two years ago, haven't had a problem. Call Cardon for advice.