Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I don't mean to be rude, but do you have any other information on your Grand Voyager? Symptoms, any testing you've done? We're happy to assist, but we need a bit more to go on in order to give you helpful advice.
P0740 refers to the torque converter clutch, are you getting any kind of engagement during highway cruising? How's the transmission fluid level/quality?
Do you have a scanner capable of activating the TCC solenoid ? If not there's not much testing you can do ... With that said the solenoid control pack is Fairly common and is likely the problem however you will need a scan tool capable of activating the TCC to verify this .