1998 ram 1500 5.9L V8 46RE
P0740-TCC solenoid circuit open
i've had this code for a little while now, but no other issues.
Truck runs fine, i do have overdrive, shifts and downshifts like it supposed to, when it's supposed to, i just don't feel the lockup after OD.\
I'm first going to inspect the harness outside of the transmission and clean up the main trans connector to be sure there isn't an issue there like a broke wire or something..
Now if all that checks out, what should i expect? I've seen several videos on replacing the Torque convertor solenoid, and you have to drop the valve body.. is it possible to do it without dropping the valvebody? i'm somewhat skepitcal of my ability to do that without screwing that up.. i can do most other mechanical things but, like Dodge, transmissions are my weak point.

 

TCC solenoid gets power the same place O/D solenoid does, PCM controls the grounds for the solenoids. Verify continuity for the ground side wire from the PCM to the trans. If that's good, probably just a bad solenoid.

Rumor has it, you *can* change them without dropping the valve body, just routing the harness can be difficult.

 

Thank you .i will dig through the wiring diagrams and track the grounds down.

 

So the only wire i can find that has to do with the TCC solenoid, according to the manual is a Orange and black wire, should i check for power or ground on this wire?

 

Yep, orange with black trace is the ground wire, but, the PCM will only ground that wire when the trans is in third gear..... and speed above like 35 or so.

 

Gotcha... so like you side, check for continuity on end to end of that wire.
Thanks

 

Wire has continuity from plug end to plug end.
i cleaned up the male plug on the trans and female connector with contact cleaner and reinstalled it... I don't know if it's just my mind being hopeful and playing tricks but it seemed as though i was cruising at lower RPM....but i have a strong feeling it was my mind playing tricks... I cleared the P0740 code and will see if it reappears

I may tap into the wire at the PCM, and run 2 jumpers to my meter in the cab of my truck to check for continuity to ground above 35 MPH/At speed to be sure the PCM is grounding...which i'm sure it is but i'd rather Eliminate as many outside issues before trying to replace the lockup solenoid.

 

If you have a nice quiet road you can drive down, little or no traffic, just accelerate slowly from a standing start, and you can feel each shift. If you have a tach, you can watch the RPM drop. Keep it below 42mph, to avoid O//D, or, just disable it with the button..... you'll be able to see the 1-2, and 2-3 shift, and then you *should* see about a 200 RPM drop when tcc engages.