A few months ago when I would start from a dead stop in my 1997 6.5 Chevy silverado, it started making a like a "clunk" from what sounded like the rear differential. It would also jerk. Here recently it started just doing it when I put it in drive. And it didn't do it all the time. I also just realized it looks like it is leaking into the driver side brakes. It was time for a fluid change anyways so I took the back cover off and drained the fluid and there was only about a quart and a half in there. I'm not sure how much is supposed to be in there, haven't looked it up yet. I took some videos (which I'll post as soon as their done uploading) of me turning it by hand and you can hear what I'm talking about. What do you guys think? Beaings?