Ok I just recently bought a 1984 Olds Custom Cruiser and there is a clunking in what I think is the rear when I let off the brake. Today I got the car up on jack stands and if the car is in neutral and a spin one wheel by hand the other does not spin at all. If in park and I spin one wheel the other spins backwards. Shouldn't the wheels not spin at all in park? And if in neutral both wheels spin if I spin one? Is this rear on it's way out?

 

The behavior you describe is normal for a non-posi axle. And you might want to double check the axle. My 84 Custom Cruiser came with an 8.75" Type P axle.

 

Good to know. I always thought when you spun a tire in neutral the other would spin in one direction or the other.

 

On a non-posi axle there are three shafts to spin (driveshaft and the two axles). If all three are unconstrained, only the two with the lowest friction will turn. In neutral, one of the brakes is dragging more than the driveshaft. In park, since the driveshaft can't move, the wheels turn in opposite directions. If you completely backed off the brakes and tried it in neutral, both wheels MIGHT turn instead of the driveshaft, depending on the friction in the trans.

 

I didn't consider one of the brakes might be dragging. Honestly I was more concerned with the clunking I hear during driving, and the hole in the floor pan I now have to fix that I thought was two small holes.

 

You might want to check your u joints also. When worn out they can make a clunk.

 

Yea I checked and those are fine. Honestly the car is fairly clean. Which makes that rust spot really weird. The floors are really clean except for that spot on the rear driver side.