I have found the cause of the sound; the propshaft being released from the PTU. I mounted a camera under my car, and went for a drive. You can actually hear the rumbling noise starting right after the propshaft stops. I went for a longer drive, and the noise appears exactly when the propshaft stops every time.
FCA on the other hand means this is a perfectly normal sound from a 4x4 system, even though it's so loud you can actually feel it in the floor of the car... No one has managed to fix the noise them selves? I'm keen to try an oil swap on the rear diff, but it annoys the **** out of me that FCA doesn't fix it - the car is still under warranty.
Video from testdrive.
FCA on the other hand means this is a perfectly normal sound from a 4x4 system, even though it's so loud you can actually feel it in the floor of the car... No one has managed to fix the noise them selves? I'm keen to try an oil swap on the rear diff, but it annoys the **** out of me that FCA doesn't fix it - the car is still under warranty.
Video from testdrive.
