Cycleclown

I have '14 5.3 crew 4x4 that has a severe driveline vibration that comes & goes as even torque is applied with the gas peddle or criuse control at varied speeds . It feels like you are driving on rumble strips even on smooth roads . I have had to my dealer who did a great job documenting it and changing fluids in trany & ttranfer case but it continues so when I return in the spring it will go back and I'm not very encouraged after reading the forum .Thanks to all who post on this & hope we get some satisfaction