I want to drain and fill my differential with synthetic gear oil, I think I need a 14MM for both drain and fill lugs? Where do I get them.. I don't think my local Sears will have it.

I hear crunching in the back going over bumps, It has gotten worse recently. I had this in my 83 300D and my mechanic replaced the rear swaybar links, is this my problem? How easy are these to replace?

That's all for now. TIA.