Shouldn't the steering wheel boss be splined to match the end of the steering shaft? If the boss is aluminum, the splines may be worn off.

well I knew why the steering wheel had a problem.. I saw the nut in the center portion.. so I knew.. just didn't fix it until now
and now it is crooked!

You drove it for two weeks without finding out why the wheel fell off?.....................Speechless...................

driving the other day and the steering wheel came off.. yes.. totally off while I was driving.. I was able to push back down on the set bolt, or whatever it is called.. drove it for a few more weeks, making sure I was pressing down on the wheel, or at least not pulling up on it.

tried to fix it yesterday.. pulled wheel off (while not driving).. that big set nut, 8 sided maybe.. was off.. put the wheel back on, lined up straight .. tightened the nut.. took for test drive.. no matter now many times I did it over. the wheel is not straight now.. straight when tighening it up but crooked after.. any ideas?