trans leaking again after rebuild

this fella seems to be a very standup guy,dont get me wrong,my wife picked up trans,when i got home i fiddled with shifter linkage and it wouldnt move, called him up and told him about it and the missing dipstick. he drove 120 kms to check it out the next day, linkage was stiff was all and installed dipstick for me. i have no garage for the demon, ive had motor and trans out twice this year and im working 6 days a week right now, it wont be out til next year. maybe i can get lucky and its overfull, i cant get a proper reading on dipstick,in neutral of course, i installed 9 litres in trans so i dont think thats the problem

Just an FYI.
Running to little fluid can foam it and cause the same problem.

My money is still on the seal or converter snout.
Not wishing that on you or anything, but that is usually where the problems come from.