I ended up putting a little less than half a quart in, brought it up to where I could touch it with my pinky. Oil looks prettty black so I'm going to change it when I change the engine oil here soon. It's only done it twice, both times after going through stop and go traffic on the interstate in Omaha, so I'm assuming it's the stop and go that's heating up the rear end. I've taken other long trips and never had it happen but they were all nice steady speeds.