Kw900B

Hello. I drive a 97 Kw900B tri axle dump truck. The specs are. 3406 B model cat.Cataac Ser# 8PN11678. Main trans# RTO16915. Its a regular 15 speed. Rear axle #RT52-180. The door tag said it has 4.56's in the rear. MY questions are these. What kind of fuel milage should I be getting? I was getting 5+. Now I'm getting 4-4.5. Same driving habits. What kind of boost should I see on the Gauge? Will do 20-23 but no more. I'm thinking it should do more than that. Where is the sweet spot on this trucks RPMS? I don't like to take it over 1600 myself. I normally let it pull down to 1200 or so before down shifting. Should I go lower? I've been driving trucks for eight years and am just learning about all this stuff. I consider myself an old school driver. Meaning I listen to the motor by ear on when to shift and etc. With that said I'm always willing to learn more!!Thanks in advance to all who respond!!

 

Thanks! I thought maybe it's just cause I'm in stop n go traffic. When it was gettin 5+ it did'nt matter how I drove it. I could drive it easy or mash the pedal through the pump. Still was 5. Just thought I'd ask. Thanks again!