you can’t fill it with the engine off, has to be running or the fluid will just pour out. It’s a pain, I had to top mine off after I did trans swap. You have to run it through the gears put in reverse, neutral and hold at a certain rpm to get everything to fill correctly all while pumping in fluid until it drips out. I put my wife up in the car in the car on my maxjax to run through the gears for me while I was pumping in the fluid, she was scared to death lol