Out of nowhere, I was unable to shift into reverse. It's a 4 Speed manual; and It is not the tranny. I can put it in reverse under the car with the linkage, but the Shifter will not go over to Reverse. There is a reverse lock on the car so the key can not be removed unless the tranny is in Reverse.

What could be stopping me from moveing the shifter to reverse?

 

well, if you can put it reverse underneath, it is a problem with the shifter

is the shifter sloppy or worn out?

also, try readjusting the linkage