turbo 400 help?

i just finished up a 67 gto for my daugter. anyway the turbo 400 was done 5-7 years ago and it seems like the converter is draing fluid back into the pan after you drive it. myquestion is what do i do to fix this? is there a check valve? thanks tranny guys mike

 

they all drain back. Depending on the wear on bushings , pump gears and related items in the front of the trans control the drain back volume.

there is no check valve

 

Do you park on a hill, did or does the car sit a for long time and is now being driven? Is it leeking out of the speedo or the electric thing that I cant think of the name right now?