Gear selector shaft seal?
If no one else had previous knowledge of c4s and you asked them how its hold it one might think that its screwed in possibly?!
But I'm pretty sure it good, I'll know tomorrow once I crank it up and put it under pressure!
And btw, the washer kind of worked for the selector shaft, it still dripped a little from the flat spots on the stud. So I went ahead and took the kick down lever off the other transmission and put it on mine, it seemed to have done the trick!