since you have a 489 case you probably have a cone type carrier --- spider gears for those carriers are NOT available anywhere --- open carrier spider gears are NOT the same as the sure grip parts -- if you are lucky maybe someone on here has a damaged sure grip with good spider gears they can sell you.-- if a clutch type sure grip was installed into your case you can buy a complete internal kit to replace the stock damaged gears. --- since the spider gears are shot the case probably is too ,,, just buy a new sure grip carrier and install it .Auburn , True trac , Power lock type.
