The rear end tag will read 3.73, 3L73, 4.10, OR 4L10 Depending of which rear. L denotes limited slip.
Door code
Look on the drivers door or door jam.
Code Axle
46 — 3.73 non-limited slip
42 — 4.10 non-limited slip
D4 — 3.73 limited slip
D2 — 4.10 limited slip