I have an 89 bird with T5. When i shift up through the gears the tranny works fine. Under hard or easy throttle...no problems. It doesnt even grind into reverse at startup. The problem I have is I cannot shift from 4th to third gear. The shifter just wont go into third gear when Im cruising in 4th...what I have to do is shift from 4th to 2nd with the clutch in then back into third. It doesnt grind, it just wont go in unless i go back to 2nd then to third. Bent fork? Syncros? Any help would be great.

 

Bent or broken keys in the 3-4 synchro, or worn 3rd blocker ring where it goes up against the keys