I have used the ATF before, however it did not do it's job. Afterwards I went to synthetic, and have had it now for 2,500 miles. It started eating it up, so I threw in 32 oz of Marvel Mystery Oil. That caused it to clean it out really well. As in it does not tick anymore. Going to get a new oil change done this Monday, so just a stop gap measure to fill her up again, I threw in a quart of Mobil 1 Synthetic.
Perfect.
Have also been using the Marvel Mystery oil in my fuel, to help clean the fuel system, this has caused my car to perform much better than it did. Which is perfect, I have more power now, and it is much easier on the gas than it was before. Running about 35 on a gallon (no AC). Which is better than the 25 mpg it used to be running.