If it's just the spider gears that are bad you can replace them and the center pin. They come in a kit.
If you have other stuff wrong, you can buy a new Eaton limited slip unit.
Most of the gear vendors with adds at the back of the car magazines sell them.
Stay away from the cone type Auburn units, they don't last as long.
Make sure everything else is OK too.
Check the gears for wear and excessive backlash or damage.
Check the bearings and look at the axles real close, also look at where the axle bearings ride on the axles for pitting.
I'm going to have an extra set of spider gears to sell as I'm replacing the ones in a 12 bolt I just bought. I'm going to 33 spline axles and a slightly narrowed rear.
If you get a whole new unit, you'll get the new spider gears.
Check my web page for First Gen Camaro suspension info:
David's Motorsports page
First Gen Suspension Page
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer
[This message has been edited by davidpozzi (edited 01-10-2001).]