2008 Ram 1500 5.7 Hemi oscillation noise? MDS?

Hi, I have a 2008 1500 with a 5.7 hemi that makes an oscillation sound under load. On flat ground there is no sound but if you go up a hill between 45 and 50 holding the speed constant and not giving it enough gas to downshift, you get a weird oscillation sound. From the driver side it sounds like it's in the back of the engine, from the passenger side, it sounds closer to the intake. There are two frequencies to it. A low rumble that happens all the time at the above conditions and a higher pitch that sounds a little like a diesel truck engine braking that happens intermittently. I've taken it to 4 different mechanics and the best I get is from the Dodge dealer that they think it might be a sticking MDS solenoid. But they are only 85% sure and it's $1000 to fix. The noise is significantly worse pulling a trailer. Enough that I'm afraid of damaging the motor. Since I primarily used the truck to pull my son's scout troop trailer, it's kind of useless at the moment. It's spent the last 5 weeks between various shops. The Dodge dealer said they have never had the problem before. Dealer says if they are right, it should't hurt the motor to drive it but if it fails it will fail in 4 cylinder mode. If they aren't, I might really damage it. Anyone else ever experienced something like this? Any recommendations? Would a tuner turn off MDS? Would it work if the MDS solenoids are failing?