Just for clarification, are you wanting a truck with 4 total axles, or three total axles? Steer, lift axle, and tandems- or just steer and tandems? People mean different things when saying the same thing. "Tri axle" dump in my area would actually be a 4 axle truck (steer + lift + tandems) , because a three axle truck is a "tandem".
Also makes a difference how you are using it. Are you doing just onsite work? Hauling a trailer with excavator? Hauling asphalt or rock for hire, or by the load, driving the truck all day every day as a dump truck?
Personally, if I was buying a dump truck, I'd want a 18k-20k front axle, and 40-46k rears. I like a spring over walking beam suspension (just because they are pretty tough and stable) , but a lot of the guys hauling all day every day, run air suspension to make the empty trips a nicer ride. That's why it makes a difference what you're doing every day with it.
If you're just doing site work, a 10 liter motor is fine. If you're pulling a triple axle trailer with a big excavator on it, you're probably going to want a little more power. Or if you're getting paid by the load, and living in hilly country, you're going to want to scoot down the road both loaded and empty. Time is money.
In my area, there's two types of dump trucks. One is the big quarry and excavating companies, that are running 2-5 year old trucks, maybe with some warranty, and trading them out and getting new trucks all the time.
The small haulers (4-5 trucks or less) and small excavating companies, mostly run older pre 2005 to late 80's pete, kw, mack, with pre emmisions motors, some of them pre electronic engines. Just to be able to work on them without extensive electronic diagnostic equipment.
So when there's issues with the truck you are buying, is this a repair yourself (you have the tools and a place to fix it, and some know how), or a "its going to someone" for repair? Because that makes a difference to, on what you buy.
