After talking with a buddy of mine, the rearend caps (gear side/ carrier side) are different sizes? If this is true, I did not mark the main caps and am ready to get the rearend rebuilt, how can I easily identify which cap goes on each side? Is he wrong, or is there an easy way to tell them apart?
Thanks

I don't think the caps are different sizes. If they are mixed up, you can compare the machine marks on the sides and bores of the caps to try to get them back in the correct locations and orientations. You do NOT want to get them mixed up or oriented wrong. If the machine marks won't tell you, you might have to use a micrometer to measure them in various installations to determine which goes where and at which orientation.