08 ram 1500 170k miles. When in between 55 and 65 mph when staying at a contant speed or accelerateing in that window the motor i believe, makes like a rumble noise or vibration that is a little loud. When i get over 70 or under 55 it doesnt do it. When you take your foot of the gas pedal it ddoesnt make the noise. Its only in that speed window
If you’re lucky it could be a loose exhaust heat shield.
If not so lucky it could be a drive shaft problem.