If you're considering a 2015 Volvo Vnl tractor truck with I-Shift transmission and tandem axle, there are some other options in the market that offer similar capabilities. Here are three potential rivals:
2014 Freightliner Cascadia
This model is known for its reliability and fuel efficiency. It's powered by a Detroit DD15 engine which offers horsepower within the same range as the Volvo D13 in the VN 670. Additionally, it features an automated manual transmission, providing similar convenience to the I-Shift on the Volvo.
2015 Kenworth T680
The T680 comes equipped with a PACCAR MX-13 engine that also falls into the 375-424HP range. Its Eaton Fuller automated transmission gives it comparable drivability to the I-Shift system of the Volvo model. Moreover, this truck also has a sleeper cab, making it suitable for long-haul applications.
2015 Peterbilt 579
This truck is powered by a Cummins ISX15 engine with horsepower ratings that match up well against those of the Volvo D13 engine in your current consideration. The Peterbilt 579 features an Eaton UltraShift Plus automated manual transmission which provides similar ease of operation as Volvo's I-Shift system.
These alternatives provide comparable power, drivability, and comfort to the 2015 Volvo Vnl tractor truck while each offering their unique strengths and brand reputations.