It wouldn't have hurt the valve body or either clutch pack. However, the oil pump wouldn't have been happy at some point. If the pump pulled up fluid and you have good system pressure now, maybe it survived. The only other possible issues would be with the bronze bushings in the front pump housing and in the rear of the input shaft. If they had been oiled during assembly, they might be okay too. The front band may have seen some heat, but I would think that if it glazed, it wouldn't shift into second as firmly as it should. I think you would notice that. You might have shut it down just in time. Change the fluid out again and see how much material is in the pan.