Read the owner’s manual. I’ll be surprised if you find the word “flush” anywhere near the word “transmission.” The only thing I recommend flushing is the cooling system. The manufacturers know that about 1/3 of the transmission fluid remains in the transmission during a standard change, and they still recommend a standard fluid change. There are too many horror stories about transmissions failing shortly after being flushed. Why gamble? Stick with the tried-and-true method.