[jay70]

my axle housing has CCA 0821B stamped on the right side, when i turned the pinion before I fulled it out both wheels turned, when I disassembled the ring and pinion I removed the crossshaft pin and bolt it was holding two little gears 180 deg apart,(I think called spider gears) which were lined up with the gears on the differential. Is this a posi unit or open.

thanks for any input

 

[7DSS]

I would have to look in the books to make sure of that number. The quickest way to tell if it's a posi is the carrier that bolts to the ring gear will have "clutch plates" and springs. If it's an open diff, you will just have a carrier bolted to the ring gear and the only thing in your carrier will be the spider gears and the pin that they ride on. I just converted my open over to posi with an Eaton unit.

 

[big gear head]

Here are some pictures that should help you figure it out. http://community.webshots.com/album/55410292AnMJrE
Notice the springs and plates between the axle gears in the Eaton posi. The standard differential does not have these. You can't see it in the pictures, but the posi also has clutch plates behind the axle gears.