GEEZ, this one stumps me. Sounds like there's something floating around in the tranny - the friction coating on the clutch packs can flake off like paint if they get hot enough.
My only guesses would be:
1. The filter clogged because of the clutch wear, but I would expect he cleaned the entire thing out after putting in new clutch packs.
2. The seal thing again. Those $&*^#@ things can be tempermental & bind up during re-assembly.
3. The valve body may not be installed in the correct orientation and/or its seal is not in the correct orientation and/or the seating surface is no longer within spec.
I wish I could be there to pick it apart.
