I went to Moneta this morning and unloaded 4 packs of lumber that I brought back from Fairview Pa. because it was supposed to have been "ground contact" but it wasn't. Then they loaded a load going to Erie, Pa. on me. I was headed up rt.220 a little south of Fincastle when I heard a loud "clunk" and the truck kind of lurched for a second. Then a few seconds later it did it again. I pulled over at the wide spot just north of town where the DOT checks trucks a lot...looked all over, under, around, and through, but I didn't see anything out of the ordinary. I called headquarters and Jeff said to try it a little farther and see what happened. A little farther was only about 17 feet,4 1/2 inches, then it made the biggest "clunk" yet. I turned around at the next cross-over to try to get to Truck Enterprises in Roanoke. And I might have made it, I was clunking along pretty good for a while, but that last stop light before you get to I-81 caught me. Then I couldn't get up the hill. I came to a complete stop and locked the power divider in. Just managed to get it onto the shoulder, inching along, loud banging and clanging at this point, but I figured I couldn't hurt it any worse by then. I was on the phone with headquarters before I got off the road, and told them to call a wrecker. A state trooper pulled in behind me, then a deputy sheriff pulled in behind him. I told them i'd already called a wrecker, so they said "OK", put some flares behind me, and left. I'm thinking it's either the rear end or the power divider's done come undone. It looked like this waiting for the wrecker- I took a photo of the wrecker truck after we got to Truck Enterprises- nice unit. Jeff came and picked me up in his pickup, now i'm sitting at home.