I had my tranny rebuilt 15,000 miles ago and the dreaded p1740 code appeared. I took it back to the tranny shop for them to say no probems exist. They did a stall test changed filter and fluid then sent me on my way with my 350.00 check in there hands. 2 weeks later the code came back. I took it back to them and again no issues. Now 3 weeks later the code reappears. I have no noticed shifting probems or erratic RPM issues. How can this be? Is this a common issue? What is your oppinion?

 

Well another one gets screwed by a trans shop.

You either need a new converter or a new lock up solenoid. Both should have been replaced during the rebuild. But i doubt they did.

 

It is my understanding, from my own experience, that the computer expects a certain engine rpm at a certain speed and if there is X amount of difference for longer than Y time then CEL and code 1740. Of course I don't the X and Y. I just know that driving too long with the TC unlocked will generate the code.