Only thing I can figure is air compressor had a piece of carbon in it making higher then normal clatter. Sounds like it did before I posted trend, and compressor is building air faster.
Time for a full blown tune.
Could very well be just a gear lash adjustment. I'd confirm that it's correct. Also idler gear bushings with excessive wear will also make noise. Chipped gears are also not uncommon like others have said.
Re-gen more and more so, going to get my ducks in row and head south east. Rough idle plus, bad mileage, and every once in awhile she will spit coolant out of the left hand side of day tank vent tube.