RPM's question about my Volvo

Hey guys, got assigned an '05 Volvo with a Cummins. New to Volvo and new to Cummins (most of my past motors have been Cat). This one acts like it runs higher in the RPM's but I'm not sure. There is a green section on the Tach that goes from 900 to 1700 and then the red section starts at 2400. I've been running between 1400 and 1700 for the most part but I know when other people drive this truck they get more speed and performance out of it than I do. Do I need to tach it up higher? I've had it up to 1900 briefly and it doesn't act like it has any more power to give so I backed off. Below 1400 it is a gutless son of a gun.

Prior trucks have been Peterbilts with Cat motors and they've always pulled well from about 1300 up but I was told not to take them past 1700.

(Rig weighs about 100,000 lbs, so this is also heavier than what I'm used to running)

 

Oh, I should also let you know that I do most of my hard pulling in 6th or 6th-HI on an 18-speed.

 

Sweet, thanks. And I thought I was lugging her at 14 on the hill.