'07 E90 335xi auto. Changing the transmission pan/filter & fluid. Drained the fluid, replaced the pan, went fine. Measured the fluid, 6 liters. With the car perfectly level, started pumping in fluid. At 3 liters, it started pouring back out the fill hole. WTF? I now have the back end as high as I can get it and the front wheels on the ground. I've only gotten to 4.5 liters and it pours out. Can someone tell me what I'm doing wrong? Thanks!