2001 Honda Civic Question: CEL P1298 and P0740

I have a 2001 Honda Civic Lx. I have a CEL reading code p1298 (ELD) and P0740 (TORQUE CONVERTER SOLENOID CIRCUIT OPEN). I have done lots of reading on these codes, and most people say the Transmission have to be rebuild. From my understanding, if I have a electrical code with the P0740 code, it's not a mechanical issue, it must be an electrical problem correct? Now before all this, my car was having issues with Engine knocking and I later fouind that I had a bad crankshaft, and so mechanic got me a used engine. Since then is when I had more issues with the car. After the engine swap, I had a CEL reading P01298 along with a P0336(CRANKSHAFT SENSOR) which had been replaced my the shop who swapped my motor. Is it just an electrical problem or mechanical ?