Low power on brand new Kenworth t880?

I purchased a new 2023 t880 tri axle dump truck with the x15/500 (productivity), allison 4500rds transmission and 4.30 rear. I live/work in SE Pennsylvania, so moderate hills. It has only 1400 mi. on it.

My concern is, it seems underpowered or has a mechanical/programming issue?

When loaded, my boost only goes to 28psi (I think I've seen it hit 30 once or twice), and always wants to stay in the 5th/6th gear range most of the time. I have to keep my foot to the floor and going up a moderate hill on a 4 lane hwy, can only get to 38 - 40 mph.

This is the first higher hp truck I've owned, and the first auto...are my expectations wrong, or does something not sound right? BTW, no error codes or lights.

Thanks.

 

I thought about that as possibly being the issue, but for what I expected the power to feel like, it would have to have a considerable increase in power. I understand being new there would be a break-in period, but I just don't see it increasing that much.

According to the shop mechanic at the dealership, it should have higher boost than the 28psi that it is putting out, that and the fact it wants to shift to higher gears, even as you start up an incline on the highway, leads him to think something isn't right.

 

I have an appointment for this Tuesday, they're going to plug it in and pull data logs as well as check all the settings and hp output readings. I'm taking it to them fully loaded so they can also test drive it, to see how poorly it performs when climbing hills. Hopefully they'll be able to figure it out, and that it's just a minor glitch or setting that wasn't right.

I joined this forum in hopes of getting insight from others, in case the dealership can't find a problem, not to mention just to learn more about these larger trucks and motors from people with much more experience than myself!

 

Yes, 11-24.5's...Gross is 80k, but here in PA I'm only allowed 73,280 (truck plus 23 1/4 ton load).

Yes! It's exactly what I would expect a truck that is set to "economy" would feel like...when I started climbing (loaded) a moderate (6%) 1/4mile long incline on a 4 lane highway the truck bogged down to like 25 - 30mph before it wanted to downshift from 5th gear to just 4th, with my foot to the floor on this straight and steady incline, the best it could do was 38mph by the time I reached the top. Maybe I'm wrong, but that just doesn't seem right to me...?