This morning I was driving home from work and I noticed a tinny noise when I put the car in gear. Went under the car to see where the loose heat shielding was and noticed a fairly decent amount of differential oil had leaked out onto the diff. and its cross piece. Just curious if leakage is normal or if this is something more serious... thanks

Should be no ( not a drop) change seal and check slack in bearings ( may only need seal )

Zero. Either the gasket or the pinion seal needs replacing. I'm not clear on where you have a leak.