May consider a full seafoam treatment instead of the trans fluid. Works about the same, but I know seafoam works too. I forget exact figures, but some in the oil for a week or for a long drive, some into the engine thru the intake, and a can in the gas tank and it should clear out any carbon issues you have. Full info should be on a thread somewhere, or google "seafoam treatment" and you can get all sorts of info on it.

Glad it fixed itself. Keep up on maintenance and you should be fine.