I have a 2015 Lariat w/the bigger ecoboost and 3.55 gears. What I have started to feel is a vibration when the motor shifts into a higher gear when just cruising city streets. As soon as it shifts the tach goes to 1100 or 1200 rpm and then the vibration. I think it mite be the exhaust drone causing it but I also wonder how that could cause the whole truck to vibrate. Mite just be the tranny slipping for al I know. truck has 1100 miles on it. Please help me if you can. I know its under warranty but would like to know if anybody else may have had this issue.
Thanks in advance.
I also forgot to add that this is most noticed when truck is cold on the first drive of the day

 

Quick?

 

My 2014 was doing the same at 5000, dealer put in a new trans I have 13000 miles on now and its starting too do it again when the trans is over 170 degrees ...........

 

Quick as in: Quick some one give me an answer that makes sense

 

I know there has got to be someone who has a high gear (5th and 6th) shudder.

 

When I took out an EB for a test drive I mentioned the exact same thing to the dealer so we took it out as well as 2 others and they all did that. Transmission was having a hard time deciding what gear to stay in when driving 50 kph on the city streets.