Yes something odd going on for sure, we paid special attention to all areas of the C5 using the Allison manual as a guide. Piston, bore and housing all like new. General condition of the Trans was like new throughout except for the c5 discs and plates (center worse than outers).
Set up pack dry with new number 2 OEM plates and discs, the same as what came out. Measured through the hole in bottom, 4 bolts and gasket on housing. It was slightly tight to the specs we had from ATSG (0.090 to 0.110) and I set it to 0.098 but now I learn factory spec is 0.070 to 0.085. Could this be the issue maybe ?