Hard to tell without a pic,lol.
But I'll guess wrong parts or bent parts.
But there is one thing ;
On occasion, the reverse interlock, inside the trans, bangs into the shift mech. You can prove this by disconnecting the reverse lever, and putting the trans into neutral. Then try to shift it into reverse. If it hangs up instead of snicking into gear; loosen the cover and push it up as high as it goes, and secure it there. Then try again.
Do not confuse this hanging-up with gear-clash which is the reverse idler gear crashing into the slider or cluster. So slam it in there, with the clutch pedal depressed,a couple of times to line everything up, then look for the hang-up.
