I picked up a survivor 98 RT Dakota that's setting a 740 and I had some questions about the code, and I guess moreover the logic behind how it sets codes. I know with some, they only set after so many key cycles. Others are instant. Here's what I am wondering about -

It sets that 740 sitting still. And I thought that 740 was the PCM notifying that it did not get an rpm drop back from the transmission when it went into lock up or was supposed to. So, I say OK, and I clear the code. With the truck sitting still. And it comes right back. Immediately.

Would that imply that the solenoid is not talking back to the PCM? OR, take a look at this picture. It looks like the wires are pulled out of the trans harness. Could that be a contributing factor to the 740?

The trans shifts fine. Just no OD.

 

looks like it's faulting due to a short, is my guess.

 

I wanted to circle back to this and post the results as a reference for others. I took it to two transmission shops, both told me it needed a "complete rebuild". However, I got one of the shops to confirm the OD solenoid was within range and firing. So that told me that since it was shifting fine the converter was bad.

I rolled the dice, picked up a new converter, $125 thanks Transtar, and I pulled and serviced the transmission and installed the new converter. She's going into lock up perfect now. (Knock on wood of course)

So in this case the PO740 was fixed by replacing the torque converter. Trans was and is shifting fine for an old truck with 175K miles.

Must be living right.

 

good deal. That's my fear, is the TCC going bad. At least you caught it before I did, when my first one went it took the internals with it.