So, I have a perplexing issue with our 2012 Dodge Grand Caravan. The only way to explain it is that the engine kind of sounds like a diesel engine when it accelerates, with a whining type sound. The serpentine belt was removed and the engine run and there was no change in the noise. The timing belt/chain was replaced along with all the parts associated, except for the camshaft actuators. The noise got a little quieter after that repair, but it is still there. Mechanic used a stethoscope and the sound appears to be coming from the back of the engine towards the passenger side. The noise happens whether the car is in gear, neutral or park. We have now just had the transmission fluid flushed and changed. Thoughts?