How can i tell what size axle my 2003 4x4 4dr blazer ls has

 

Most likely it is the 7.625" rear. But you can run a google search for "GM Axle Identification" and you should get quite a few results that show the exterior features of the axle so you can identify it.

 

sorry it took so long to get back to you. I looked online at the axle identification chart but it didnt do me much good since im in iraq and i cant remember the exact details of my rear axle. However i did call 4 wheel parts and i asked them what size axle was in the 2003 blazer and they said it was a 7.5 i know that the only real difference between the 7.5 and the 7.625 is the spline count but does anybody know if gm even used 26 splines in the 2nd gen blazers.

 

Per the website posted below, yours is a 28 spline
Chevrolet / Chevy S10 Blazer & Pickup Rear Differentials - GM 7.5" & 7.6" Rear, '00 & up,GM 7.5" & 7.6" Rear, '82-'99 - 26 Spline,GM 7.5" & 7.6" Rear, '82-'99 - 28 Spline,GM 8.5" Rear - 30 Spline,GM 8.6" Rear, '99-'08,