85 base model Camaro. With both rear wheels off the ground and transmission in neutral. If I turn the passenger rear wheel forward it turns good. If I turn it backwards after forward it will go half a turn OK and then lock up i have to turn it forward about a turn for it to turn back. Then lock's up again. Makes a clunk too

What do you see inside it while it's doing this? Where does the clunk come from? Is the car in park while this is going on, or what?

It's in neutral. Both wheels are off the ground. can't tell exactly where the clunk is coming from, my hearing is very bad. I can feel it more than hear. The car has sat for at least 15 years. I'm getting close to test drive. Right now I'm putting new front calipers and flex hose. The rear drum break on passenger side had a broken spring in it and would not turn at all when I was loading it the day I bought it. I fixed the spring issue and it turns forward great. I noticed after I had it back together it had the snag happening randomly. I thought maybe I didn't have it in neutral good. But it does it even in gear. Only when turning it in reverse direction. Driver's side goes both directions without stopping. But if I turn the driver side forward the passenger side will turn about half a turn and snag up

Guess I need to take the differential cover off and the drum. Gotta change the fluid in it any how if it's not junk.