I have noticed that my 08 RAM, with a HEMI w/MDS while cruising between 60 and 65 with the cruise on, the rpm will hunt between 1600 and 1900. It is like the converter is locking and unlocking. It does this on flat ground. Does this have something to do with the MDS? It drives me nuts and seems like it would be wasting fuel and lock-up clutch life.
The truck is stock and has about 1100 miles on it.

Thanks,
Jimmy

 

My Dad and I both have an '07 and they both do it. It doesn't have to be any certain speed, cruise or no cruise. The fella at the dealership said it was the MDS...dropping and/or adding cylinders as needed. I don't know if that's true or not. It sure doesn't seem like it shouldbe doing it, though. Oh well..........

 

Well, if the converter is locked, the rpm should not change. I'll let it get a few more miles on it and take it in, I guess.

 

Mine does the same thing. They just put in a new tranny and it was doing it before and it is still doing it now. Do away with the MDS, put in a good TQ lock program, and all would be well.

 

Yep, it's the MDS, if you had aftermarket exhaust you'd be able to hear it. The rpm's jump up when you go down to 4 cylinders to compensate for lossed power. It's no biggie, you're saving gas when it does that..

 

OK, Thanks.
I don't think I'd want to hear it

 

Mine does the same thing. I had 000 miles on it when I got it and now it has 2000 miles on. it still does the RPM huntingas you call it. I set the cruze at 65 and the rpms bounce around constantly from 1800 to 2000. I just figuerd i was how the MDS system works. If the engine or trani die on me we'll then I guess iLL JUST HAVE TO PUT THE LIFETIME WARRENTY TO WORK.

 

With it only being a 300rpm change then its the mds and not the tranny hunting.
The mds will also kick off when the geo youre drafting changes lanes or you run into a bunch of bugs.

 

Haven't hit too many bugs yet [sm=wootwoot.gif]

I just figured if that even if it is dropping to 4 cyl, the converter would stay locked on flat ground, thus keeping the rpm steady, but I guess not.

 

Hi All,
I've recently purchased an '06 4dr. with HEMI w/mds. I noticed the rpm shift also when the mds went on and off. I don't think the tranny is the problem. I think it's an electrical load difference that effects the tach causing the rpm shift.

Keith
'06 Lone Star Edition