Just wondering if there is an easier way to find out how many splines my rear axles have without having to tear everything apart. Thanks
Don't tear "everything" apart, just remove one back wheel and look at the center section of the rear axle. Might even be able to get away with just popping off a center cap.
31 spline will have 3 holes in a row. 28 spline will have a large rectangular-ish indent.
*this is almost always the case, but apparently there are early versions of 28 spline that have 3 holes like the later 31 spline. However, if your rear axle is original to your car this should not be a possibility. If I'm wrong, the experts here will correct me ;-)