The dual solenoid goes out the most. I normally replace all 3 and install the superior correction kit or transgo. https://globaltransmissionparts.com/...kaAmdrEALw_wcB

 

There are two shift solenoids. There is also a torque converter clutch lockup solenoid and a pressure control solenoid.

Depending on which solenoid you're talking about you could have missed shifts, no torque converter lock or unlock, or almost no power if the pressure control solenoid fails to low pressure.