I recently swapped blocks on a 2002 3.0 flex with a 2004, didnt have the torque convertor in correctly when mating trans to block. Removed Trans, corrected, re-installed. Engine starts but Trans will not go into any gear. I understand this can damage to the pump. Are there any other component's that will cause this other than the valve on the pump, the pump itself and the Electronic Pressure Control Solenoid? I havent checked fuse 41 yet, I will tonight. I dont know if the transmission was working before I got the truck and it sat over a year before I bought it.
Please help.

 

Welcome to the forum

Reads like you damaged the pump, so will need to pull the transmission and tear down to replace the pump

I did this on my first automatic trans install, 40 years ago, fresh rebuild to, lol, expensive lesson for me

No solenoids are used for "in gear" that's strictly a mechanical engagement by the shift lever on drivers side or transmission
You could unplug the 16 pin connector on side of trans, so no solenoids at all, and it would still go into gear, D or R, just wouldn't change Drive gears very well
So not going into gear mean pump is broken
You can also check trans fluid level, engine off and then engine on, level will DROP quite a bit if pump is working, as it should


What happens if you don't seat the torque converter onto the transmissions input shaft is that the pump tabs and slots are not aligned so when you push trans onto engine the pump tabs are push back and that breaks the pump

The pump is at the front of transmission so you might be able to replace it by removing the bell housing but.....................I don't think you can align it very well so might pump out ALOT of ATF around the seal when engine is running, so probably not a great idea