I'll check the frame again. Everything looks solid and no signs of movement, but maybe I missed something.
It's definitely not the driving habits, if you rode with me you'd agree. The only time I turn under power is while on I think I'll change fluids again just for the fun of it, that, and it's been three years and about 8,000 miles.
I'll do a closer inspection of the trailing arms themselves while I am crawling around under there.