B&W Companion slider stuck installing

Thanks guys, The post isn't down far enough for the pin to go in the hole. I got under the truck and looked at it. The pin is now in the pulled out and locked position (which actually rotates it right out of the hole) Since it just got in a bind on the first time I set it in place, I am really hoping it pulls right out with being strapped up to a forklift. I liberally soaked it with penetrating oil over night. I am heading out to the dealer in a little bit to see if it works its way out. fingers crossed. I will let you know. On this model the pin is a welded part of the base itself. The base weighs around 100 pounds and I haven't even gotten to the point of teaching the uprights yet. It is basically all one unit.