I have a 2005 GC Limited with the Hemi, bought new, maintained on schedule, with only 72k miles on it. Recently it's begun to throw a P0740 code which says the Torque Converter Clutch solenoid is open. Dealer says transmission (R45RFE?) should be rebuilt.
It drives great, shifts smoothly, will shift into 5th at highway speed, but just won't go into lock-up mode. Fluid level is correct. I can clear the CEL and it will stay off until I go above 60 mpt or so, when normally it would go into lockup.
Will continuing to drive it damage the transmission? Could it be a sticking solenoid? Anyone had this issue and solved it without a rebuild?
I would run, not walk away from that stealer, unless they've gone through the complete troubleshooting list. If everything BUT the TCC is woking normally, I think I check that electrical circuit and solenoid/switch valve first. My first impression would be (if they haven't).....another ripoff specialist. Notice how they zeroed in on the last item? Did they tell you they went through all the ts steps indicated in the shop manual? Did they eliminate all other potential causes? I seriously doubt it. For sure, I'd get a second, and maybe third opinion before I did anything. It won't hurt anything, except maybe fuel economy with it not working, unless there is something coming apart internally. May want to do a fluid/filters change first, to see if there is anything abnormal in the pan and/or on the pan magnet. Here's what the FSM says are the likely causes of P0740:
RELATED DTC P0750 PRESENT
TCC SWITCH VALVE STUCK
TCC REGULATOR VALVE STUCK
INPUT SHAFT SEAL RING CUT
TORQUE CONVERTER AND/OR INTERNAL TRANSMISSION
Please keep us posted on what you find out.
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I had a new solenoid pack put in, valve body cleaned, plus changed the ATF and the two AT filters. That didn't solve the problem. Still shifts smoothly but no TCC lock-up. No other codes besides 0740 and 0700. I'd like to troubleshoot the electrical connection. Anyone done that?
Am I right in thinking that the TCC solenoid is included in the solenoid pack that I replaced?
TCC lockup is controlled by the same solenoid that runs 1st and reverse. Once you're out of first gear, the L/R switch valve switches over and that solenoid then controls a different circuit.
Transgo's shift kit includes a 'self cleaning' L/R switch valve. It's a little plug about the size of two pencil erasers that slides into the valve body just like the stock one. I've installed them twice.
FWIW, I feel this valve, it's circuit or the T/C itself must be at fault. Not the trans itself.
Let me know if anyone tries this, I've had this code for 6 months now, just got tranny and 4wd service done and the same code is still posting. I figure I have until next year when smog is due. Really no dealer techs out there have come across this and solved it?