P1810 code after trans swap

I have an '00 impala 3.8 and recently swapped in a motor/trans out of an '04 impala. I am now getting two P1810 codes "Transmission Fluid Pressure Valve Position Switch Circuit Malfunction" according to my scanner. If I clear the codes, the transmission will not shift to 3rd or 4th. If I leave the codes it shifts normally, but slightly hard into 3/4.

I have added some seafoam trans tuneup.

Is is possible the '04 trans is not compatable with my '00 computer? I know there were some changes from '03-'04. Is there something else I can check?

It took 7 quarts of fluid to fill the transmission after the swap. I initially assumed the code was just because I started the engine before the trans was full.

It's possible that There could be a compatability problem between the tranny and PCM......it's also possible this problem was already in this tranny before you swapped it.....