Yes, not a difficult job if it is only replacing the solenoids but ptorblem could be more than that.
DTC P0740/40: LOCK-UP CONTROL SYSTEM
1. Using scan tool, retrieve A/T freeze data. Clear DTCs and road test vehicle under same conditions freeze data was recorded. If DTC returns, go to next step. If DTC does not return, problem is intermittent. Check transaxle and PCM connections.
2. If any other DTCs are present, repair those DTCs first, then recheck for DTC P0740/40. If no other DTCs are present, go to next step.
3. Test line pressure. If line pressure is within specification, go to next step. If line pressure is not within specification, repair hydraulic system as necessary.
4. Replace A/T clutch pressure control solenoid valve "A"/"B" and torque converter clutch solenoid valve. Turn ignition off and clear DTCs. Ensure engine is at normal operating temperature. Road test vehicle in "D" position at speed greater than 55 MPH for more than one minute. Check for DTCs. If DTC P0740/40 returns, replace transaxle and torque converter. If DTC P0740/40 does not return, system is okay.
DO NOT perform this test procedure until all other DTCs have been repaired.