2011 Durango Citadel 5.7L 44K miles

so im having an issue that is really bugging me. when im on the freeway, if i let off the gas and start coasting i can feel some drag from the vehicle. the issue is intermittent, but happens most of the time. i know its not the brakes dragging, but thats what it feels like. and whats even more weird, is that sometimes if you watch the tachometer you will see it do a quick dip and you can feel the vehicle slow down even more!! its as if there is some kind of engine braking going on. and i know its the engine and not the brakes because when i let off the gass and feel the drag, i can shift into neutral and the drag goes away!! it then feels like your truly coasting. today i took it to the dealer and they did 4 TSB flashes. that did not fix the problem. the flashes they did were, 21-004-13, 08-024-11, 08-110-14, 18-035-11 so im wondering if anyone has any ideas as to whats causing this. im assuming its software related, possibly ignition mapping, or maybe even the torque converter. please give me your thoughts!

 

Normal transmission operation. It is downshifting anticipating a stop. This is confirmed by the fact it does not do it in neutral.

 

This is NOT normal at all!! It is definitely NOT downshifting. This condition would never be intentional as it is inefficient and can cause poor gas milage. I have to get back on the gas to makeup for the lost speed. Also, if it were down shifting, I would see my RPM's climb, not dip! And why would my transmission be anticipating a stop at 80 MPH??

 

K.. You asked for thoughts. No need to yell.

 

What is the engine speed at when this happens? Is the transmission maybe stuck in a lower gear? If you tap the gear select lever to the right to go in to the manual shift mode does it change the engine braking? What gear does it display when going in to manual mode? Is the Tow/Haul indicator on?

-Rod

 

the engine speed is around 2000-2500 RPM's at around 70-80 MPH. if i bump the stick, it will indicate 5th gear. the issue still continues in manual mode. i have played with the tow/haul with no effect. the condition exists in either mode. i feel like it is related to the torque converter. like i said before, the issue is intermittent, and if i let off the gas and it is behaving like it should, the RPM's will start to slowly back off as you coast slower. however, when i let off the gas and the issue is present, the RPM's will actually drop a little as if the torque converter is slipping a little and allowed to turn slower than what matches the tranny. then in addition to that, i get an occasional dip in RPM's by about 500 or so, and you can feel yourself shift forward in your seat like you tapped the brakes real quick or something

 

I'd be more inclined to think the torque converter is staying locked (versus slipping) when the issue is present, meaning your driveline remains completely connected to your engine versus unlocking and letting the torque converter "freewheel."

I'm not very familiar with the transmissions in these. Is there a single connection for the locking torque converter that when unplugged will only prevent the converter from locking and not effect other systems? I'm aware of several other makes/models where that's the case.... If so, I'd try disconnecting that to see if the issue is due to a locking torque converter that remains locked. If you never experience the issue after disconnecting, that would point that direction.

-Rod

 

trax95008,

I would recommend bringing your vehicle back to the dealership and advising them that your concerns are still present after having the updates installed during your previous visit. It can also help to take a test drive with someone from the service department in order to specifically point out what you're experiencing.

If you would like assistance in scheduling an appointment, please feel free to reach out!

 

After doing some more research, it appears that what I'm experiencing is the iDFSO system kicking in. I had no idea this system existed. Chrysler has been using it for 6 years now. Which raises the question, why didn't my service writer or tech catch this based on my description??? What I explained exactly matches the condition created by the iDFSO. That tells me that they aren't even aware of this technology being used in their vehicles!!! It's just a bummer that I'm sensitive to feeling the effects of it. Just like MDS. Most people aren't aware of it, but I sure am! Now if there was just a way to disable this...

 

I don't think you can disable iDFSO. It is used to save gas. Many different brands of cars use it today. When you take your foot off the gas, the converter remains locked to spin the engine and the injectors cut off.

Why not adjust your driving habits?? I feel the deceleration too, but I've gotten used to it.