I have an 82 gmc 1500, trying to fix the horn and replace the steering wheel and the center shaft has dropped low enough that I can't even get the factory wheel back on.
That shouldn't happen unless the column steering shaft is disconnected from the flex couplier. Carefully put the large nut back on the shaft and use a large pair of vise grips grab the nut and pull up as you try to wiggle it up and down, watch it closely, you don't want to damage the bearings, so don't twist. Once it is up to the proper place you may want to block the shaft out in the engine compartment to hold it until your finished.
Search GMC Sierra Classic 1500 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
GMC Sierra Classic 1500 Experts