spider gears

I've got a 79 nova, hasn't been on the road since '98 and last week first time driving it since spending 4 years rebuilding it. Was told it used to drag at a local 1/8 mile. Axle seal started leaking so I'm gonna replace bearings and seals and when I popped the cover off I found this clip in the...

Hello everyone, I purchased a 8.5" 10 bolt a while back with posi and 4:56 gears; the spider gears in the posi need to be replaced, there is a big chip in one of them. Everywhere I look it seems you can only buy spider gears for open rear ends only. This may sound like an ignorant question...