Cummins X15, what's the word?

[Rig Wrench]

Just got the second x15 thru the shop. 565-1850 torque this time. 3.90 gear with an 18 speed in a daycab W900. Seems to have plenty of power. Very responsive. Its permited to gross 117k so it'll get a pretty good workout. I was quite pleaded with the seat of the pants feel compared to stock 2250-2350s ive driven. Only complaint is it vubrates terribly at 600rpm idle. Which I hear is normal.
The owner has another x15 605-2050 heavy haul tractor with around 80k on it and is very pleased so far