Negatory; I had an exhaust leak months ago but have replaced every gasket short of the head gasket, including the exhaust gasket.

On adding tranny fluid; is it something I can leave in the oil for a while or do I need to do an oil change shortly after. I just did a full synthetic change so I'd rather avoid wasting that if possible.

I've also been running 1/2 a bottle of Auto-Rx since I change the oil about 1,000 miles ago and it doesn't seem to have done anything.