ok, I don't know exactly when this feeling first started but driving down even the smoothest of roads was feeling bumpy. I rotate and balance regularly. Over the past month or two, the duh, duh, duh feeling I was hearing and felt was getting worse. I figured I just had a bad tire although toyota told me I should get another 15K miles out of them. In the past two weeks, the duh,duh,duh added on a frequent roaring in the cabin. I got new tires thinking this was the problem. As soon as I left sears with my new michelins, the duh, duh, duh was still there. I took the truck right back and the sears tech drove it, saying he thought I had a wheel bearing bad. I, a few days later, went to toyota service, who said it was bad and also my center diff. was bad. Does this help any ? If not, I'll try to explain more.
PS I did bring the old diff. home with me. I don't know why, I just did. I don't have my receipt from toyota with me right now but believe the diff. price was like 1200.00 . All together for the diff., the wheel bearing , and new from brake and resurfacing was like 2,400.00. Their hourly service is 75.00