What's That Ticking?

Here's another maybe, as it confounded me for quite some time. Same symptoms as yours, the ring gear on my converter was .030+/- out of square. Slightly contacting the back of the block, no witness marks until a bit of rust developed on the converter. I slid the thinnest washer I could find (around .020" IIRC) between the flexplate and each lug, problem solved.