This is designed to plug the transmission side of a Torqueflight 904/998/999 torque converter.  You can use this if you need to store or ship a torque converter to keep dust out, or prevent leaking.

I designed this for my AMC 360 run stand, to allow me to have a junk TC to act as rotational mass when filled with ATF.  For this application, i printed solid out of TPU and used 2 constant tension clamps.  It was snug going on, and required some taps with a mallet.