intermittent rattle/grinding noise

Ok, so I've been dealing with a rattle/ grinding noise coming from the rear end of my 95 rodeo. The first time I heard it was last summer, I had just come down out of the mountains and when I got back on pavement it started making the noise when I was making hairpin turns on a windy mountain road, so it was a high torque situation. I did not hear the noise again until this past February as I was heading up the freeway at about 65 in heavy rain. I thought my rear end was going out so I came direclty home and popped off the back cover of my rear diff. The ring and pinion and diff assembly looked fine, The oil was pretty old and broken down so I put it back together and refilled it with oil.

I thought the problem was solved, that is until a couple weeks ago when it made the same noise in almost the same conditions, 65 straight freeway in heavy rain. I came home and checked my diff fluid and it was fine, so I thought maybe the rear u-joint is going out. So I decided to replace the u-joint. When I put the new one on there was a notable difference in the amount of play in the driveshaft, upon inspection of the old u-joint I found a couple of broken needle bearings and evendence of where the needle bearings were wearing into the joint. So obviously that was the problem this whole time, until about an hour ago when I heard the same damn noise on the freeway in heavy rain (Northwest Washington, when isn't it raining?). Does anybody have any ideas? help would be greatly appreciated. Thanks!

no worries, I think I found the problem, for real this time. The center driveline support bearing is all but gone, and it doesn't look too difficult to replace.