So, I decided to check my rear diff fluid on my 04 Envoy - and the plug was stripped and very tight. I was able to get it out and check the fluid, and I was able to put it back in (for now), but I was wondering if anyone know of any part number for the plug, or if a universal one would work with the right thread (if one exists). I did find a listing on Rockauto, but the image makes it look plastic and appears to be physically different (mine is just a threaded plug - a pretty normal diff plug).