Hello all! I'm new to the forum. My big problem led me to seek help. My '93 3000GT (base) won't move when put in gear. It all started one morning when I was driving my son to pre-school. As I took off from my parking lot I noticed it was jerking and struggling to move. It got me to the school fine and on my way back, it worsened. It really struggled to move. I stopped and tried the reverse and it was working until suddenly it stopped. It'd go on gear fine but it won't move. I had to push it home (luckily I was 2 blocks away).
Here's the problem in a nutshell: Car goes in gear but doesn't move. My mechanic thought it was the clutch. He took the tranny off to find a relatively new clutch in there. So before he starts guessing, I thought I should research on my own.

PLEASE HELP!

 

Maybe something with the u joints or axle shafts?