Calibration code is the number on the side of the computer, which can be found in the front left corner of the engine compartment. Axle code can be found on the tag that is bolted onto the rear axle cover or there is some sort of code/letter designation on the decal that is on the dirvers door jam.
+1! If you need some further clarification... Computer is just to the right of the fuse box. Axle code sticker is usually in the "5 o'clock position" on the cover.
