Shifting problem with 833

Hi All,
This is my first post here....so bear with me.
I am trying to figure if I need to rebuild my 833 tranny or if I have over looked something.
First off...I have only had the car (72 440 Duster) for a few days and my first test drive was today and the car failed badly.
The shifter was badly worn when I got the car and I have replaced all the bad parts hoping that was all that was wrong with it. The car shifts fine just sitting with eng off...but under power...it is VERY hard to get first gear. Someone said it was the bearings have gone bad causing poor alinement. I got no noise or whine form the tranny nor could I feel any problems/vibration through the shifter. I can get 3rd easier than 1st but it's really hard to get any gear at times at a dead stop. It's no fun holding up traffic while finding any dam gear just to get out of the way. I'M going to take another look at the shifter & linkage and the clutch throw distance...but feel it's not the problem. Bent shift fork? Or time for a rebuild? Thanks guys, Bud :sad1: