I seem to remember if you remove the oil fill hole and rotate the crown wheel, the ratio is stamped in the edge of the wheel. Difficult to find on some. Not on all wheels. I did not know the color codes but I do now! I've also seen a Technical Service Bulletin at some time that had a listing for several of the common codes.
Last edited by Little Italian; 03-22-2018 at 01:59 PM.