X15 efficiency idle vibration

[Pete379]

I have a few x15s and they all idled just as you described when they were at set at 600 rpm.i bumped them to 720 and it smoothed out considerable

I am not familiar with the Allison transmission but I do have experience with x15s and Eaton automatics. As far as it pushing at idle with the automatic, With the Eaton ultra shift plus transmissions and there are settings in the transmission software that control this. I believe the setting was called urge to move and could be altered from the factory setting to stop the push you are describing. Do you know if the Allison has software settings that can be altered?