Power-Lock sure grip...8 3/4??

Here's a pic. And you're right; the rebuild kits are $180-ish. The units themselves are anywhere from $5-600.

Cheif's right. That's a standard Dana power-lok used in 8-3/4's until 69. Very good unit. That's not what I was referring to earlier. I thought you were talking about the power lock module you install in a open diff. to make it a locker. You can get a rebuild kit for them for less than $100 unless they've went up a lot in the last 6 months since the last one I bought.