Brand new 07 Durango 5.7 Liter Hemi MDS. I havea 1,000 miles on it and my question is...when I first get on the freeway, I set the speed control at 65 mph and my rpm reads 2000. After a couple of minutes, it drops to 1700 rpm. Does the rpm drop happen the same time that the 4 cylinders cut out? Or is it just because it takes that long for the computer to change the rpm?

 

C9:

I believe that last rpm drop will be your torque convertor clutch locking up. You will notice a small delay for this especially when the temp is cold out. The computer will not allow the TCC to lock up till a certain trans temp is reached and of course when the rpms are a little higher the engine/trans heats up a little quicker.

I would keep an eye on it, but I think you'll find out it is operating properly.

Don

 

The revs will actually rise a couple hundred rpm when the MDS engages, rather than fall. This is mainly to avoid detonation from any lugging while the motor is on only 4 cylinders.

 

I have an 07' with 1,000 miles on it now and when I set the cruise at 65 mph it will raise the rpms! I was wondering if that is the indication that the MDS is engaged.

I REALLY question this whole MDS 'feature'. There is no indication light or anything in the guage cluster to let you know when you are in MDS mode and in the manual the section that explains MDS is like a 4 sentences!! What gives... is Dodge just claiming that this actually works?? My question is how do you TRULY know you are in MDS mode...

Also Cloud9 do you notice that when you climb from 65-70 that there is a distinct 'Whine' noise?? It is definitely loud and noticeable to annoy the hell out of me when I set the cruise at 70 mph. Any ideas on this noise that I am hearing on a BRAND new Dodge Durango 07' Hemi??

 

What is your RPM at 65. Mine is at 1700 RPM at 65 when I frist get on the Freeway and set it at 65 the RPM is at 2000 and then drops to 1700 RPM. I went a short trip and got 21 MPG

 

Man... 21 mpg! I am not getting anywhere near that. I commute each day on the highway and set my cruise at 65 mpg. The Rpms hover right at 1900.

I have been getting 15.5 mpg. Once again... I wish I knew more about this MDS 'Feature'. No indicator light... hardly ANY explanation of it in the manual... no instructions on how to utilize it .... etc.