a904 stator sealing rings...

I resused the a904 stator sealing rings, (metal ones) and the bushings in drums look real good, so reused them to, was recently rebuilt before I got it. but what I have is full clutch apply , get thud noise... and all bands/etc apply, but have excessive air leakage form the center area where the drums ride together on the stator shaft, assy, well I my opinion is more that normal, for air checking when doing a rebuild, how much is acceptable? should I take back apart and install Teflon scarf seals? or am I over thinking it. just finished the tf-2 valve body overhaul modification rebuild. and ready to install next. so I f I need to this tis the time to do it...