Transmission replaced check engine light P0740 code error.

Hello Miron, When the transmission was replaced the TCC solenoid could have been left unplugged, or not plugged in all the way. The connector on the solenoid could have been bumped during installation, they are very easily cracked or broken. Also the wiring to the solenoid could have been pinched as well. If you clear the code, and it comes back as soon as you start the car, I would suspect one of the above issues. If the code doesn't come back until the car commands your torque converter to lock up, the solenoid could be bad or the converter may not be responding. There is also a filter screen in the solenoid, just unbolt it and clean the screen. Most of this should be done be a reputable transmission shop, but if you are familiar with the things I've listed, you can give it a shot. If you have any more questions you can call me at 602 253-2553. I hope this helps, Jeff