Has any noticed a vibration while driving on the highway around 65-70mph or at 2000rpm. I just noticed it after new tires, but I had them rebalanced but it did not make a difference. I have the 4.6 with an automatic, with about 81,000 miles.
Any ideas????

 

Yep..mine has done it since it hit 3,000 miles (now have 8,600). In the range of 62-66 mph about 50% of the time. Nothing major though...and I have noticed that the vibration is not there until after driving the truck a short distance (warms up). The slight vibration is coming from the rear...I can feel it ever so slightly in the seat. I had the rear tires rebalanced by Good-Year..no improvement.

It is not the tires...I have already rotated mine and it is still there...same as before i nthe rear. Possible warped rotor(s)??

 

Sometimes worn components make themselves known when new tires are installed on vehicles due to the increased friction at the tire/road interface. You might want to check for worn suspension or steering components. Also, make sure that your tire dealer is checking radial runout of the tire to the wheel - I've had dealers replace new tires because of excessive radial run-out and newly acquired vibrations went right away. Just my $.02

 

My truck has had the shudder for a while, but I have learned to deal with it. Just recently, while merging onto an interstate, the vehicle began to vibrate, and stall under throttle. You could tell it was coming from the torque converter. You could put it a neutral and it would idle just fine. Put it in gear though, it would shake and stall. I was able to limp the thing home and it cleared up after it was shut down for a while. I took it in to the dealership and have discovered some interesting information about the 4R70W transmission.

There is a very good possibility your truck has a poorly engineered torque converter. The poor design produces the vibration that you are feeling in the steering wheel. What RPM is your engine turning when you feel the vibration? My guess is that it is around 1850-2000 RPM right after the converter has locked up. I believe the flaw to be found in the lockup component of the converter itself.

Sorry for the rant, but I wouldn’t be so upset if I wasn’t going through a transmission replacement at only 28,xxx miles! To add insult to injury, Ford provided me with a rental. Enterprise Rent-a-Car provided me a Chevy pickup. At least this one is drivable!