To drain and fill, park the car on a level surface and cut the wheel so you can access the level plug on the driver's side of the transmission. Drain the fluid out after driving the car around the block to warm it up a little. Then, add fluid and run the engine w/level plug out until it stops running out. Again, takes about 4 quarts. I don't know what kind of restriction will happen from an inline filter, so I wouldn't do that.