Has anybody had a really hard time getting the fill plug out of their rear diff cover? I tried to break the plug free with the cover in place and I had no luck. I was changing the diff fluid and wanted to inspect the gears as well, so I took the cover off. I sprayed two types of penetrating oil on the plug and let it sit over night. The god damn thing is still seized! The problem is obviously caused by the manufacturer not coating the steel plug with anti-seize before installing it into an aluminum cover. I'm gonna heat the cover and back the plug out. By the way, I'm not one of these guys that uses a ratchet to break things free, a breaker bar is the only way to go. I will get the plug out, I was just wondering if this is a common problem.