New to boats and have a problem. 1986 volvo penta 280. I pulled the upper unit to replace ujoints and bellows. I'm trying to put back together but the input shaft (ujoints) won't turn. It turns a small amount then hits something and will not turn anymore. I removed the back shifter plate but nothing else was taken apart. When I shift it turns the direction that the vertical shaft TRIES to turn. What am I doing wrong? I really want to take the kids on the water this weekend. Any help from more experienced people would be greatly appreciated.