Axle Shaft For '80-'90 4Wd GM Truck. 31 1/2 Inch, 28 Spline. USA Standard GearUSA Standard axle shaft for '80 '90 4WD GM truck. 31 1 2, 28 spline. 31 1 2 long 28 spline 6 lug Fits 1980 1990 GM 8. 5 truck with 4 wheel drive Features and Benefits: 31 1 2 inch long 28 spline 6 lug Fits 1980 1990 GM 8. 5 inch truck with 4 wheel drive Details: AAP UDA 4: 50 Axle Nut Included: No Shaft Length: 31. 5 inch Application Summary: 1987 1991 Chevrolet Blazer (Rear) (Drive: 4WD Note: GM 8. 5 inch. 28 Spline 31 1 2 inch. Length) 1981 1986