I goes down like this: lately I've noticed a rythmic fluctuation in my cruising rpm of 150-200 aproximately. This went on occasionally for a few days until a CEL lit up, code 1740. I know this code has to do with the TCC and overdrive solenoid (as per some previous discussions on the forum.) I did a little experimentation. Driving up and down my neighborhood street, accellerating and slowing, never exceeding about 45 mph, I notice no problems. The transmission seems so function flawlessly. It's not until the truck is cruising. The fluctuation is most pronounced at about 61 mph in overdrive. I could not notice it when not in OD.

So any theories? My theory is that the torque converter is locking and unlocking, thus causing the rpm fluctuation and the CEL, but what do you guys think?

 

Isn't that what the TCC does? It tells the torque converter when to engage and disengage.

 

Thats what I understand.

 

Change your TCC and I think you should be good.

 

Thank you very much. I just needed a second opinion.
I've looked on Advanced. Any idea where I can find one?

 

Yes, go here: http://www.transmissioncenter.net/dodge.htm
Then scroll towards the middle of the page...well a little past that and there you have it!
Also, skim threw this thread. It's relevant to what your doing.
https://dodgeforum.com/forum/2nd-gen...alve-body.html