Horsepower Needed

An 18 does not have as low a gears as a 15 or 8LL, they will work, but not as easy on the drive train and clutch, and a quarry rig is steady stop and go all day.

 

Will they be EPA 07 or younger trucks you will buy?

 

If your 46 ton estimate isn't a mis-print than you really need some
heavy trucks. You will destroy a "highway" truck pretty quick. With that
kind of weight even small hills become an issue.

I would try to find some older Heavy-Haul trucks. Heavy frames,
heavy axles, heavy clutches, large cubic inch engines. Engine horsepower
does matter but I would definitely stay away from 11 to 13 liter engines. Small
cubic inches don't have the low end torque you will need. A 400 horsepower
15liter with some serious low gears will work.

Also be prepared to do some serious truck maintenance. Grease jobs, tires,
etc. Dust will be a huge issue. If you want to keep the a/c working you will need
to stay on top of cab filters, engine air filters, etc. You really need a set-up to
pressure wash your equipment on a regular/weekly basis. If you don't they will
turn into nasty/filthy mud caked heaps that nobody wants to drive.

Seriously if this is to be a long term job than I would consider buying off-road
haul trucks. They are designed for that job. They have super heavy suspensions,
super heavy axles. I am guessing that you will spend considerably more up front
but in the long run you will save money. Another issue is cycle times. These haul
trucks will tip a full load in seconds.....they are easy to drive.....have heavy brakes.....
turn super short. If 30 yards is the most you want to load there are lots of these
smaller haul trucks out there. Many of the companies I see have gone to the 45 yard
trucks. Might be able to find some decent used 30 or 35 yard trucks. Deere and Volvo
both build a decent truck.....CAT does to but they tend to be higher priced. Good luck.

 

double post...……….

 

Actually, after some more thought. 46 Tons is 92,000lbs plus 40,000
truck weight gives 132,000 total weight.

Off-road haul trucks are the only good way to go here. Unless this is
just a short-term gig......you will destroy highway trucks. They will not
stand that kind of abuse.

 

I think like other post it depends on how fast you want to go. Then you pick the transmission and rear end to do that and give you starting ability when stopped. Guy on Satellite radio Kevin Rutherford is pretty good on knowing transmission ratio and axle setup

 

Like the guys have said, it's all about the gearing.
I used to run OTR pulling trains at 135,000 lbs with an NTC 350, 15 spd direct trans and 4:11 gears on 24.5 rubber, didn't go fast but got the job done, ran 60 - 62 mph all day long at 2000 rpm.
In a pit operation you would want steeper gears or or lower rubber or a bigger engine to compensate for the lower torque and hp of the 350 hp engine.

Give some thought to Allison 6 speed autos, good off road trans.

 

I see a lot of Allison Transmissions used in the oil patch for their off road trucks. They can put anybody behind the wheel and not worry about breaking it.
For manuals, an 8LL would be a common choice, they are only rated up to 1650 torque. So an engine in the 400-500 hp range would do.
A ‘Highway’ Truck would do as long as it’s spec’d for it, heavier frame, definitely 46,000 lbs rear ends.
I had a truck with a 450 Mercedes 18 spd 40,000 lbs rears at 4.10 ratio. I pull 140,000 lbs super B train hopper bottoms. Occasionally I load right out in the field in soft freshly turned soil. I never had a problem getting it to go, but blew out the bearings in the front diff after only two years. I use 46,000 lbs rears now. There was one field I climbed out of, the truck was slowing down in bull low first pulling up onto the road, so a deeper rear end would have been nice. For you something closer to 4.55 -4.89 or deeper.

 

You need one of these, off road ready for your pit has a payload capacity of 46tons and your drivers wont rip drivelines out of them.