can't get pitman arm on...please help

alright so I was changing the gearbox on my barracuda and I have the new one on and i cannot get the pitman arm to slide onto the splines, I know there is a wide spline and it looks lined up but I'm not sure, is there any special trick to doing this other than turn the steering wheel a tiny bit get under the car check and repet... the pitman arm moves foward and back up and down so I'm lost... kinda on my own on this so any help would be awesome.