Does it have the stock exhaust?

 

Yes. I've never notoced this until today becuase I just got over 500 miles and started driving over 55. I can't put my finger on it to describe it, right at 70, it does it. No other time. There is no physical vibration in the steering or pedals, just this cabin "reverb"? feeling. I crack the window, but can't tell if it is there or not due to the noise. If I let off the gas, it goes away, but if I hold steady at 70, it does it. If I accel slowly, it will gradually go away at around 74. If I accel hard, it goes away immediatly.

 

That sounds like it could be the clutch packs in the differential. There is a TSB on it. Its covered by warranty. Do a search to check that out.

 

Like Goody said...you drive it at 70 MPH with one of the mech inside...btw, no vibration here.

 

Sounds like a driveline vibration. Maybe his driveshaft isn't properly balanced. How does the clutch pack tsb come into play at 70mph?

 

I got the same problem when my car was only around 500 miles. The first dealer where I bought the car told me that wind noise. They acted like I was a troublemaker. I went to the second dealerwhoaccepted the problem and after asking Ford representative, they replaced the driveshaft that was unbalanced.The noise was gone.

 

Stupid as this sounds...

You said the problem goes away when you roll the window down, right?

Well, it might be something with the auto window function, and that the windows aren't going in at the correct height, so it's causing a pressure difference inside the car;this will sound like a vibration.

The windows on my GT roll down an inch when I open the door, and then roll back up when I shut the door. The owner's manual says that this is part of a way to keep the cabin noise down, and may need to be reset/readjusted. I forget the exact step to go through resetting it, but I know it's outlined in the owner's manual.

I only mention this because my mom's Corolla has similar noise issues, and it happens when the back windows are rolled down a slight amount. It actually starts sounding like a helicopter is flying directly overhead, and causes a vibration throughout the car.

 

Well, I took it to the dealership today and drove the tech around. As soon as I hit that swwetspot and it started, he agreed that it was the driveshaft. They checked for anything that may be loose, but fond nothing. They didn't have a means to check if it was balanced. They ordered a new driveshaft and will hopefully get it and replace tomorrow. They told me to just stay under that speed until then and I'll be fine.

 

I hope someone will answer my question. I HAVE EXACTLY this problem. 2007GT California. Vibration between 65-70. Only in 5th gear at 2000rpm.Balanced Drive shaft- still there.They replaced the drive shaft. Still there, but only in 5 gear, and at 2000 rpm at approx 68mph. Take it out of gear and goes away. 4th goes away.
I am frustrated and never had a prob. with a mustang before. I had a 2004 Mach1, and 2003 GT. Never a vibration. I am affraid that it will never be fixed. I do not think I should ignore it either. Please help!!! Thanks

 

It's not the helocopter type noise that so many are confusing the topic here. It is only exhaust harmonics. Nothing wrong with your car. If you had the windows down, and varied your rpms at 20 mph, you would here it then too.