Chrysler Repair: 98 grand voyager p0740 code, torque converter clutch, plymouth grand voyager

Question
Hi Roland
I have a 98 Plymouth Grand Voyager and i recieved a p0740 and p0700 code. I bought an OBD2 scanner and this is what I recieved. What would be my best course of action, the van runs fine, so far!

Thanks
Allan

Answer
Hi Allan,
The 0740 says that the torque converter clutch lock-up device didn't actuate properly at some point. You probably notice that when you reach cruising speed there is a slight decrease in the rpm of the engine, almost like a mini-gear shift, and that is because the torque converter input and output turbines have been tied together as an economy move (no slippage). It is not of itself a big problem.
It could be that the trans fluid is a little bit low, so check the trans dipstick once you have driven for awhile. If you have to add fluid only use ATF +4 type fluid, never use Dexron. Add it a little at a time thruough the dipstick tube, and don't overfill.
Other than that, if it keeps coming on it may be due to a low pressure problem in the transmission itself. A trans shop would need to access if that were the case or not. If so, it could either be the internal pump of the hydraulic fluid switching box (called the solenoid pack) that is at fault.
This is not going to cause a driveability issue in and of itself. It may cause a 5% decrease in gas mileage.
That is how I see it.
Roland
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