Vibration between 55 and 65 MPH
New user here - I picked up my '16 GT Premium on April 28th and noticed a slight vibration. You can hear it as well.
It's a constant drone at those speeds. Tried several things to diagnose it:
I get up to 60 MPH, windows up, air off, tunes off, 6th gear, feel and hear the vibration.
Down shift to 5th, maintaining 60 MPH and get the same results. I go through 4th and 3rd while doing 60 and nothing changes.
Still at 60 MPH, I push the clutch in, put it in neutral and coast. Vibration is still there.
It's definitely a balance problem or misalignment in the driveshaft. I read a post from a Ford tech who had the same issue in his own Mustang.
He said he noticed paint markings on the pinion flange and the driveshaft and they weren't lined up. He dropped the driveshaft and aligned the paint markings.
It solved his problem. I told the tech currently working on my car about it and he noticed I have 2 paint marks on my pinion flange and 1 on the driveshaft and none are lined up.
He's currently consulting with Ford engineers and they told him to drop the whole rear end and test it to failure. Looks like I'm getting a new rear end soon. I'll keep ya posted.