Ford 9” posi locked up

[Joris69velle]

Hey guys.
So i installed this ford 9” in my firebird over the winter. Used unit. Came from a circle track car or something. Anyways. Got gear oil and additive in there but cant get the clutches to break loose. Ive done my circles in a parking lot. Is there anything else i can try?
Recommended fluids?
A more violent shock to it??

Or do i accept that its probably just worn out and seized.

Kinda annoying cuz i swapped out my welded 10 bolt for this reason

Thanks
Joris

[Bieb]

Since the circles did not work, you may have to take it apart. They are pretty simple to take apart and reassemble. If you leave the pinion in place and only remove the ring gear part, you should not have to mess with the crush sleeve and pinion depth upon reassembly. Just set the pattern to where it was and the backlash should be good.

[Alwhite00]

So what's it do when you drive it in a circle? Did you look at the 3rd member? I've seen a few circle track guys weld the rear solid.

[Joris69velle]

Thanks for the replies. Im probably not going to take it apart again anytime soon.
And if i do ill have to pull the whole rear end out of the car because i had a hard time putting the center section in the housing.
It looked like a posi but i actually didnt look at it too good when it was apart.
The inner tire skips when i do my small circle.

[oleyeller]

If it came from a dirt car, the diff is probable a spool not a posi.

[Joris69velle]

If it came from a dirt car, the diff is probable a spool not a posi.

Took the pinion out and yes theres a mini spool in there