CEL P0740

[Hemi4X4]

2018 Power Wagon with 68k miles. Getting CEL with the P0740 code. No other codes present. Truck runs and shifts fine, no shudder, not hunting gears, shifts thru all gears as it should, RPM's are normal, no change in fuel economy.

Based off of research it could be a few different things, however there seems to be noticeable symptoms along with the code.

Fluid level is correct, fluid is clean/no burnt smells.

I have a feeling if I bring it to a trans shop they will want to do a full rebuild. I'm just not convinced it needs a rebuild being as if you did not see the CEL on you would not be able to tell that something may be wrong with the transmission.

Anyone else experience this or have any insight?

[Retired BLM Rig]

P0740 relates to the torque converter clutch slipping. TCC lock up usually only occurs at cruising speed, so it might feel like it's shifting normally at lower speeds, but the final locking of the torque converter isn't happening. At cruising speed you should see an additional drop of 200-300 RPM when lock up occurs.

If you do a lot of towing or hauling and don't use Tow/Haul mode, this can lead to premature TCC failure. If you drop the pan to do a service look for an excessive amount of clutch material in the bottom of the pan. If everything else is functioning normally, then you can probably continue driving it until greater failure occurs.

Maybe try clearing the code and then only drive the truck in Tow/Haul mode to see if that keeps the code from returning.

Just my .02¢.

[Bill2014]

Driving at highway speed, watch your Tach reading and see if the trans is locking and unlocking several times a minute in the 5th or 6th overdrives. It should stay locked up even with very slight presses on the accelerator.