How do I get a faster truck

First, I'm not worried they cut the legs off my truck, but they cut the nuts off. It's a 2012 Pete 587 with an advertised 450 isx, eaton 8spd. It's a lightweight truck, I've been running the smokeys, and the truck gets so bogged down, this evening I went to the low side of the range selector, had to run 4th on 40west in North Carolina. It's downright dangerous. Truck and load weighs in at 73,277. Does it need to go in the shop, or is it the trans and rear end killing it. It seems to run great, no problems, no dpf lights. Guess what I'm asking, this truck was speced for regional Texas, Oklahoma runs, and I run east coast. How do I go about asking for a truck with a 10spd or 13spd, if that will even benefit me, I'm sure they are all 450 hp trucks

 

Power, I can deal with the speed limit, that's a company deal. I'm not joking, in the 3 weeks I've been in this truck, I have yet to pass or even stay close to another company truck. What I was asking, what's the best way to word this to the shop.

 

Not an exaggeration at all. I'm going home in 11 days, I'll let them know. Sunday evening the petro replaced both fuel filters,

 

It's about 5/8th, I've filled it up twice. It doesn't stumble, miss, or hesitate, just pulls like I have 160,000 behind me. Both of my last company trucks were similar, except 500hp, and it was a day and night difference. Am I driving this wrong? Downshift to a lower gear at 1050, and up shift at 1500. Any less that 1450 on a slight grade, and I might as well just downshift again.