I have a 5 speed Ranger, and I can not go past 2nd gear. on 1995 Ford Ranger

I can use first and second, but when I go back up to neutral to slide over to go into 3rd, the shifter will not move. I tried turning the truck and seeing if I could get it to slide back and forth in neutral, but it wont budge. I was told to take the boot off and look for a pin to push back down, but there is no pin anywhere that I can find. I had a trans dropped into it about 3 months ago, and the clutch is new withing the last 6 months.

same thing whether or not it's running? Trans under warranty?....I know that's probably a silly question , but got to ask.