Most all GM rear axles are marked on the housing tube with a letter code. With out knowing what year the axle is it won't do you any good. You will have to go inside and check the ring gear. It most likely needs cleaned and new gear oil anyway. Rotate the ring gear till you find the part numbers and date code. The ratio should be there as well, 41-10, 39-10, etc... With this information you can figure out what and where it came from. Joe
