Isn't there an adjustment on the steering gearbox to help with this? I read about sending your steering gearbox off to a couple different companies that rebuild, improve, and beef them up.

 

Not sure about 1996 vans.
Older ones have an adjustment screw on top with a lock nut around it.
Check the connection to frame first, on mine the bracket attaching steering box to frame was cracked and presented as play in steering. Was common on the older vans.
After 20 years and lots of miles it could be just plain worn out ! In that case adjusting the play would only wear it in a worse way.
I would probably replace or rebuild out of abundance of caution. Bad steering can be dangerous.