i have an 88 Irocz with 9 bolt and 2.77 accroding to the tag and also have another tag on rear end that says no spin on it. The problem is when turning both rear tire skip like a locker is in place, The car has set for 2 years and i have chaged the fluid and added GM Additive, my question is where to get a new posi unit or what to do to this one so its not harsh to drive, it feel like it will break a shaft . and plus when you get on it from a stop you heard a loud squeal,not tires from the diff as if it was slipping.

 

TTT

 

My car does the exact same thing. I have the same rearend too. When I turn really tight it almost feels like the car bounces a bit or if its on loose gravel you can hear the tires slipping. I think posi units are hard to find but you should be able to get yours rebuilt.

My car has 260k kms and has given me no trouble even though its always acted this way.

 

go to www.diffsoultions.com or www.9bolt.com. the 2 links take you to the same place. all of the borg info you need is there.
i would say give yuor carrier a lil bit of time and it should be ok. as for being stiff when yuo turn i wouldnt sweat it that much, mine will "scotch" when it goes around turns under normal to firmm accell. my friends 88 GTA does the same thing. im having to drive to nashville soon as a friend has anothher 9 bolt for sale and im gonna but it. only thing is his exsisting carrier is toast but i have one we are going to shim and install.
if your rear has slack then chances are the carriers internals need shimming. i think there is an article on this in tech .