Really, you need to make an all out attempt to find out where your rear axle was made, Hyper, or whoever, so you can buy the needed parts from them, that way you'll have a better chance of getting matching parts, being a 4 pin, and a 31 spline, might be someone made some bad choices along the way to a 31 spline, 2" axle. Better find out now, while there is time, do some detective work, and find out. Bob!