I think you need too start over and pull it out and inspect the case for cracks,i have seen many leaks but not from the top of the case,unless it is blowing out the dipstick and running down.
The overdrive going out is the end result of the problem you haven't fixed yet.
If your builder is just replacing burnt clutches and nothing else you haven't fixed the problem.
If you pull the o/d out and replace it it will happen again