Just took a road trip and noticed a disturbing vibration at highway speeds. I have a 2012 fx4 with 6.5 bed, ecoboost , max trailer tow package, 26000 miles on the clock. This vibration feels like it is coming from the rear and at first thought I think warped rotors. Cruising the interstate at 75-80 mph and any braking light or hard would produce the vibration. Secondary roads at 60mph or less produce zero vibration. Which leads me to believe the rotors are fine.
I have searched the threads about shudder and vibration, but did not see anyone describing my exact problem. I haven't seen the dealer yet. Would like to get some ideas about what to check before I see the dealer. Thanks.

 

The first thing I would do in a case like this is get the wheels/tires balanced. Tires can become unbalanced as they wear. Or if nothing else rotate the tires first and see if the same thing happens. I had a car that acted like this once and when I rotated the tires it was quickly obvious which tire was making the vibration. In that case it turned out to be a tire with a broken belt.

 

its time for an oil change anyway. Will give that a try but have never heard of an unbalanced tire that shakes only when the brakes are applied at 75mph.

 

My last truck had a shake between about 35-40mph when braking, rebalancing the tires and a new alignment fixed the problem for me.

 

Could be a hard spot or flat spot in tire.

 

Was going to try and make it through winter with the factory tires but may replace them and see if the problem goes away.

 

It could be the ABS activating. My 13 would do the same but at only certain speeds and certain pressure on the brake pedal.

 

Hi WFO,

It looks like some folks have already chimed in with some suggestions; be sure to let us know if you decide to get your dealer involved. I'll be here to help once they've diagnosed the truck.

Crystal

 

It does sound like an ABS issue. My 13 doesn't have it but, I've driven work vehicles that have had that issue and it was the ABS. If it was tires then it would shake regardless of braking.

 

The slightest imbalance that can be felt while driving at speed seems to be magnified when the brakes are applied on my '07 which ain't a lot different. Recently I've been chasing an imbalance that seemed mild, even tolerable at times but coming off the exit at 65 and jumping on the brakes made it worse. Finally nailed the imbalance, got the tires as perfect balanced as ever they have been, put the two roundest on the front .... and for some reason ...... my brakes are smooth now!

 

Problem solved. I am now the proud owner of a new 2014 F150 Limited. Will post how I got a deal that was too good to be true in the proper forum.