I have not a lot experience in driving a truck or even mechanic and I have just recently bought my Kenworth w900L (AG 460, 18 SPD, Cummins ISX 600 HP) of year 2006 from local
car dealership, and actually I didn't expected so many problems at the beginning, because I had many conversations and discussion with mechanics before purchase. I have sometimes transmission malfunction and when shifting from high speed. Also it is hard down shifting sometimes with strange loud noise and vibration. Maybe drive a truck is just not mine, who knows, but I think such problems with new truck is abnormal.