The reason I ask is I'm in the market for a newer,low mileage Ram 1500 with the 5.7 Hemi.

I'm curious about the multi-displacement-system on the 2006 and newer Hemi's.
It turns off 4 cylinders when not needed. It supposedly shuts off fuel and spark and also has some special lifters on those cylinders.

Anyway, is it a smooth transition?
Have you had any problems with this system?
Does it affect towing ability?
Any thoughts on long term durability?

Thanks

Jeff

about two years for me, so far so good. Can tell mostly at idle, feels like a slight miss. actually, the sad part is that it doesn't really do THAT much for mileage improvement. I average 13.3 in city, stop and go, with quad. If you are towing, can turn off MDS on shifter with press of button. ALso noticed MDS goes off around 75mph +/-. so highway mileage is just okay.

For me, it is okay??
P.s. also heard MDS can be disabled permanently if desired.

I've got 60k on a hemi Durango with MDS. No problems. The transition to 4 cyl and back is smooth. It helps fuel consumption at light cruise - say 60 MPH. Above that it needs all eight cylinders so the improvement isn't huge.

2007 Ram 1500 5.7 Hemi 4x4 laramie. I have 20,00 miles on it. 16mpg around town and right at 19 out on the highway. No problems so far from the MDS.

Thanks guys.

I read they are staying with the MDS for the '09, so I guess they believe in it.

Jeff

It is a near indestructable motor and Chrysler tests have proven that. MDS is great cruising on the hwy and does not affect power or reliability whatsoever.

My 06 Ram Sport had 25,000 hard miles put on it in one year, with no issues.

SRT engineers recently said in a press release that the MDS system improves MPG about 8% on the 5.7V8 but they felt that did not matter on the 6.1 and so left MDS off because of a valve lift problem.

On the current 5.7 Rams
the aerodynamics is so brick like
the MDS can't keep operating much above
the 60-67 mph range
particularly on blacktop pavement or windy days.

I have seen enough internet forum posts with pictures of detonation damage on 5.7 v8s, and a few crank bearing problems, that I am not convinced the 5.7 is "bullet proof"....but no engine is perfect and the Magnum 5.2/5.9 and V10 have had problems too.

"Hemi Tick" is not really an engine killer
but if you buy a truck that has had the STAR fix of the exhaust valve guides it is a plus not to have the noise.

see archived post below:
===
Chrysler has known for some time how to correct
"Hemi tick"
but so many engines and $ are involved
that they are afraid of issuing a recall or TSB.

They have a solution that your dealership can find
by checking their
"Star Online" computer data base
for solution number K59926684 or K21050787

The ticking problem is that the valve guide internal diameters are too big,
and the solution involves putting in new valves with oversize stems.

If you are still under warranty
Chrysler will pay for this,
but if you are out of warranty
it is a very expensive repair.