Drive train rattling. Goes away in 4x4. What is it?
I have a 2013 Lincoln Navigator.
It developed a rattle/grind under the driver side towards the front.
It happens at the low end of the gear range when accelerating. Usually only
gears 2 - 5. It seems like it is related to the amount of torque.
It Rattles for a few seconds, there is a clunk, and it's gone.
It only happens in the "2x2" setting.
If I switch to "4x4 Auto" or "4x4" it will not make the noise.
The tranny needed work and was just replaced...that didn't stop the noise.
I have replaced the 4x4 Vacuum actuator in the engine compartment...that
didn't fix the noise.
Any ideas on what this could be?