I'm having some issues with my '01 cummins with the H.O. motor and 6 speed tranny. I'm just over 98,000 miles with the original clutch. In the past few weeks, while I am in gear, if I decelerate quickly I can hear a clunking noise under the cab and also occasionally a metal-on-metal scraping noise. Then just last week, when the RPMs are low and I accelerate, the whole truck wobbles as if out of alignment, but again only while in gear. This seems to be more noticeable when down shifting and at low RPMs. When the RPMs are up, the wobble goes away. Any suggestions as to what this might be? I'd like to get a few opinions before I pay a fortune for a mechanic to take a look! Thanks.