I am trying to figure out which gears are in my car ... still. Thje build she said 3.00 convential rear end. When we turned the tires it looked like 2.73 gears.
That is NON locked -- I get that but it acts like a "detroit locker"
Raise one side of the car and see if you can turn the axle. I have seen some rears that were run low on oil (read, broken) that act that way when both wheels are off the ground, but spin (relatively) freely when one wheel is on the ground and the other not.
I have also participated in creating a "redneck locker" by welding the spider gears. We did it to the Maverick in the late '80s to run it on the oval track. Although it worked for us, I do NOT recommend that procedure unless one is prepared to replace many scattered parts in the near future. A mini spool is what we should have done.
If it were mine, I'd drop the pumpkin and count gear teeth, and look to see what kind of limited slip it is. A couple bottles of gear lube is cheap insurance.