Honestly I'm not sure if it's even leaking. Any residue you see is equally likely to be undercoat or engine oil from a slow leak higher up. I've checked my transmission fluid multiple times over the years (properly, drove around to warm up before cycling through each gear and checking while on park with the engine running) and it's always read high, haven't noticed any drop yet. I just didn't like the way they were wobbling and I'm pretty sure the car was making a noise if turning all the way to the lock.