10 bolt posi question
 

Hi

I just picked up a 71 firebird with 10 bolt posi (at least i think). If i spin rear tires forwards they both move. If I spin backwards then forwards the rear end make a racheting type noise and the tires do not spin then it "catches" up and both tires spin.
Is this 'normal'?

Second question - when I removed rear differential had no fluid in it - the ring and pinion where nice and clean the posi case? had a little surface rust -i added fluid, what is the chances this rear end is ok?

thanks in advance for assistance.

If you had the cover off that would have been the time to see if it is a "posi" type carrier. You can check by jacking up one side of the rear end and leaving the one tire on the ground. Put a torque wrench on a lug nut on the opposite tire and see how much torque it takes to rotate the tire. Block the car to be safe.

When you took the cover off did the insides look like this

or this? this is a 12 bolt, non posi. i think the factory posi will have that "s" shaped spring, like in motorhead's pic.
or it could look like the second photo, wich is another type of posi. i guess basically, if you see springs, its posi. and if it is posi, be sure to use the "limited slip" gear lube in it.

No fluid? groan--you may have bigger problems. If the car was driven AT ALL, whatever you have is probably toast. . .

OMG I better change out my 78 suburban rear end that I forgot to fill with lube and drove for about 10 miles 15 years ago.