My check engine on and code p0741 is coming up and dealer says i need a whole new transmission.

Question edited for clarity. You don't need 'So' as the beginning of a sentence, dive straight in :>D
Please always include full 'year make model' in all questions as the first 3 words.

Sometimes codes can be transient, they are just at the point of flagging the code because many codes are based on time. For example, my car threw a code for the thermostat the Lexus dealership said I needed a new thermostat fitted.. I said to my Tire Guy / mechanic who is more honest than most, I have no problems, no over heating etc. He read the code and it was something like 'the coolant temperature does not rise to 92' F within 90 seconds. I got him to change it all all was fine.

So ignore the code unless it comes back. If your mystery vehicle has a transmission dipstick, check the fluid level

One reason for requesting 'year make model' is that some faults are common to a particular vehicles, a 'known issue'. Google

year make model P0741

P0741 OBD-II Trouble Code: Torque Converter Clutch ...

YourMechanic https://www.yourmechanic.com > Articles
P0741 is a diagnostic trouble code (DTC) for "Torque Converter Clutch Circuit Performance or Stuck Off". This can happen for multiple reasons and a mechanic ...

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Testing it first is the best way. Videos that may help.

https://www.google.com/search?q=2008+Kia+Optima+LX+2.7.+Need+to+know+how+to+fix+code+P0741

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Does it die at stops or with foot off throttle and coasting? The overdrive light coming on like that is the transmissions equivalent of the engine check engine light. Fault has been detected and code stored. Would suspect with information provided that the torque converter clutch is locking up but not releasing. You may be able to have this code retrieved with an OBD2 scan tool or at local parts store. You are looking for codes in the 700 range as these are all transmission related codes. ie P0741 or P0742. The P0742 is for torque converter clutch stuck on. P0741 is TCC stuck off

Here's a link to your code. P0741 OBD II Trouble Code

Just take car to AutoZone to use their Diagnostic Code Reader and then they can look it up and tell you what is wrong and part that you should replace.

P0741 Ford - Torque Converter Clutch Mechanical System

The Engine Control Module (ECM) detected excessive transmission slippage or no TCC solenoid operation. Check the transmission converter clutch selonoid. can be low on transmission fluid, clogged filter.

Check your transmission fluid. This is a common transmission code. Torque converter clutch not locking up. You may or may not notice a difference in the driving. but defininately dont let the issue go without further investigation. the result in this light could cost you a transmission if you drive it too long without repair.

The OBDII code P0741 is vague. It indicates a transmission issue but isn't specific due to all of the components contained in the transmission. It's best to have it checked out at either a dealer or a transmission shop to avoid doing any further damage.

yes they are all right, i suspect that this vehicle uses encrypted software for the gearbox computer and this is the reason for the different codes ,i never use a code reader as on europeon cars they just show cannot connect to vehicle ,i use a voltmeter and a dwell meter plus a frequency meter and a scope to diagnose problems .So i suspect

P0741....Torque Converter Clutch Circuit Performance or Stuck Off

P0507....Idle Control System RPM Higher Than Expected

that this dealer doesnt have the correct diagnostic software because their code is a generic code as well as the first one ,A GM dealer code would have been P1507 and this code doesnt exist in the GM list of codes ,i think they are both right and need attention but the gearbox code is a fault with the front clutch operating mechanism ,i would advise ripping teh autobox out and fitting a manual gearbox ,lot less hassle