Did I make a mistake?

[compslow]

Hey Everyone,

I had a 2014 Mustang GT M6 that had a Whipple installed on it and decided I wanted to upgrade to a 15+ auto with hopes of pushing the stock motor a bit further. I really wanted to find a Competition Orange car so I started my search about a year ago. I finally found the car I wanted, but it was ten hours away. I decided to move forward so, I flew out and purchased the car.

On the way back home, I noticed a slight vibration. It's not something that rattles the car apart, but it is very annoying and noticeable in comparison to my 14 or, really any other car I've driven.. Now that I've had the car for few months, I've been able to nail down the vibration to start at 50mph. It continues through 60mph, then fades. It comes back in at 70+mph and increases noticeably as the speed increases. I took the car on the track a few months back and at 105mph the car shook pretty bad.

I would like to get everyone's opinion on what is causing the issue??

Thanks in advance!

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[Birddog 29]

Check the tires one may have knot in it. That can cause vibration like you described

 

[Shifting_Gears]

Check the tires one may have knot in it. That can cause vibration like you described

Yep. Tires first for abnormalities. If they check out, wheels next for being bent or could be something as simple as a wheel weight fell off.

If it were me, it would go have the tires balanced after a visual inspection of the tires. If that didn’t fix it, you’re looking at checking suspension next.

Definitely wouldn’t write the car off as a bad purchase at this point. The S550 is lightyears ahead of the S197.

 

[AmericanLegend]

If after checking the tire/wheel balance you still have the vibration problem...check the driveshaft.

 

[13GetThere]

I had the same issue with my F250 4X4 after replacing the factory tires with Goodyear snow and mud tires. They just wouldn't balance well. Even replaced one tire, but at best they would balance just inside spec. according to the tire shop. They started vibrating at 42 MPH, stopped at about 60, and started back up at 70 to 75. It wasn't bad, just annoying. I put up with it for a few years, and when the tires showed signs of uneven wear, I got a set of Michellin highway tires. Problem solved.

 

[Cobra Jet]

Check the very large driveline vibe thread in the Issues/TSB sub-forum on here.

Most likely it’s not tires, it’s a driveshaft issue that was a very known issue with the 2015-2016 platform regardless of trans type and if GT or not.

 

[Bikeman315]

No you didn't make a mistake but why in G-ds name would you take your car on the track with a vibration issue. Do what the others have told you and get it fixed. Then go back out on the track.

 

[Phatpony]

Yep, what everyone else said. My experience with Jeeps is that vibrations that are speed dependent usually are tire problems but I wouldn't rule out a driveshaft issue either. Tires are the easiest to rule out. Got any Mustang buddies willing to swap wheels/tires to rule them out?

 

[GreenS550]

Tires or bent rim first. But if you feel it in your butt, I would guess it's the driveshaft. I had a very similar problem with my 2005 S197 GT. I replaced the driveshaft. Nope. The pinion gear flange that the DS bolts to was made incorrectly by Ford. Replaced it and the car was totally smooth.

In my younger years back when u joints didn't last more than a couple of years, they were the culprit.

Hopefully, not a bent transmission tailshaft or something like that. Does it have a lot of miles? Any sign of real abuse by the previous owner?

Another possibility is a real out of alignment rear suspension I suppose. Had that issue with my Mountaineer and the 4 wheel alignment fixed it.

 

[compslow]

Thank you for all the replies. I should have mentioned that I had the tires re-balanced and also changed out wheels and the problem continued.

On another note, the vibration is worse with drag wheels on it. Same speed range, just more noticeable.

Track wise, I didn’t think the vibration was bad enough to cause anything catastrophic to happen, but once I felt the strong vibration at high speeds I made the call to keep it off the track until I figure this out.

I feel the vibration in the steering wheel and gas pedal mostly. I honestly don’t feel it in the shifter handle or the seat. At 85, the car shakes enough to blur out images in the rear few mirror.

If it were the driveshaft, wouldn’t I be able to feel this in the shifter and what not?

 

[compslow]

The car has 15k miles, and was completely stock when I got it. I didn’t notice any signs of abuse.

 

[Smokey613]

The vibration may be the reason the original owner sold/traded it.

 

[GreenS550]

So, assuming it is not rpm related, i.e. vibrates and shakes the same mph regardless of the gear it's in it seems to indicate either wheel bearings, driveshaft, axle half shafts.

The drive shaft is a 2 piece with a center carrier bolted to the floor plan. If you raise the car you can inspect it. Make sure it's bolted tightly. Check the front wheel bearings. 1/2 shafts.

 

[offroadkarter]

Sounds like you're part of the club

https://www.mustang6g.com/forums/threads/vibration-between-50-70-mph.15990/

Mine got fixed after a replacement driveshaft + re-balancing said replacement driveshaft. I've heard/read of others fixing this by replacing the entire rear differential.

 

[compslow]

Not the club I was hoping to be apart of lol. Sounds like I should have the dealer take a look at it. It is a Ford Certified car so hopefully the additional 1 year warranty will take care of it. I’f it’s the driveshaft, I’d really like to just purchased a aftermarket solid driveshaft but, I don’t want to do that until the vibration issue is fixed otherwise the dealer may point to that when inspecting the car.

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