I'm back! I crawled underneath and adjusted the kickdown. It is a 4.2 lever, so I used 72 inch pounds and backed it off two and one quarter turns. No change. The awful sound on a firm 1-2 shift is still there. There is no sound on the 2-3 shift, even on hard acceleration. I also tried a manual 1-2 shift (held it in low then manually upshifted to second) and the rattle/clunk is still there. It is an awful sound. At this point, I am beginning to wonder if the rear planetary is giving up on me? Based on an operation manual on this transmission, it seems to be the most likely culprit since it is not engaged at all in 2 or 3. I still have reverse, but it does still shudder/shake ever so slightly in reverse. Thoughts?