Dual Mass? Vibration at certain RPMs...
Past couple of days I've noticed a vibration at around 1600rpm in any gear when driving normally. It feels like a deep bass tone because it's so fine...almost like an exhaust drone/resonance, but coming from the motor/trans. Although it's barely noticeable right now, I want to get it figured out ASAP. I've also noticed that when I'm a little bit more heavy on the throttle there is a more harsh vibration (still barely noticeable) at around 2500rpm. It comes only with engine speed, not vehicle speed, so it's in the drivetrain, not suspension/wheels/tires.
Is this a sign of the dual mass flywheel going out on me? Whats the best thing to do, replace with new, or replace with solid? I doubt this truck has had a clutch put in it, and it's got 172k so it might be smart to change the clutch soon as well.