Just had my transmission flushed, filter changed, and new fluid put in. I`ve done this every 30,000 miles, now have 120,000 miles. When the mechanic was done he told me he saw about a table spoon of water in the transmission fluid. He had no idea on how it might of gotten there. Was asked if I driven in high water, I said no I didn`t. So my question is how can water get in the transmission fluid? Noticed that the tranny seems to shift hard at certain times like a pounding sound when changing gears up or down.