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Spec My New Used Truck


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I going to be adding another truck to the fleet. My last 2 were Fords and loved them both. This one will be for a hired driver. Back in '78 I drove a '74 F model with what I was told was a 300+ and a 5 speed. It proved to be a tuff one. This new job will be hauling bulk cement in a pneumatic tanker for a dedicated customer. Its about 110 miles each way and mostly level highway. Since Ill be buying the fuel, mileage is a big issue. I want BIG numbers. The truck should have a sleeper just in case of bad weather or breakdowns. I HATE computer driven trucks. Every computerized vehicle Ive owned has let me down, even the trailers with ABS. Im looking for a deadly reliable truck that wont break on me or call in sick. So help me guys,

What model tractor should I get?

Which engine and hp?

Which transmission?

Rear gear?

Tire size?

My current ride is pulling a van and rarely sees over 1500 rpm. It is a 3406B,400 Cat with a 14609B trans with a splitter added(.6 OD in high gear, .74 in "direct") 3.58 rears and LP 24.5 tires. This combination was getting me 6.85 mpg average for the quarter until ULSD came along. Now it is minus at least 20%. It does the same type of short haul work. Im hoping that the cement tank will have much less wind resistance and make the mileage easier to get.

Thanks in advance.

You'll never go wrong by doing right.

Who do you call when the lawmakers ignore the law?

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CX (Vision) conventional with Maxicruise and 6 speed Maxitorque for on highway or 10 speed Maxitorque if you need more reduction. Get the small sleeper- it's the lightest. I'd look for around a 4.00 ratio rears on 11-22.5 tires, that'll give you a range of 35-55 MPH in direct for the side roads and about 1500 RPM at 60 for economy on the main roads.

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There is only about 30 miles of this trip each way that is 55mph or less. Its all paved. The only gravel is in the customers driveway. The rest is 65mph divided 4 lane. Id like to see the truck be able to do 65-70 and still be under 1500rpm. Its been a long time since Ive been in a Mack. Maybe its not cut out for that sort of thing. I think the six speed would be fine. I got along great with the 5 speed in that old truck.

You'll never go wrong by doing right.

Who do you call when the lawmakers ignore the law?

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There is only about 30 miles of this trip each way that is 55mph or less. Its all paved. The only gravel is in the customers driveway. The rest is 65mph divided 4 lane. Id like to see the truck be able to do 65-70 and still be under 1500rpm. Its been a long time since Ive been in a Mack. Maybe its not cut out for that sort of thing. I think the six speed would be fine. I got along great with the 5 speed in that old truck.

Allegedly, Mack engines get their best mileage around 1550-1600 rpm.

I always hear Macks are far from the lightest truck out there, but I see plenty in bulk tank service.

I have an 18-sp with a 3:86 ratio and 22.5 tires....which puts me at 1475 rpm at 65 in top gear, 1500 plus a couple at 70 mph.

I can't give you accurate mileage because I don't go on the same exact run every day like you're planning on doing, however it varies from 5.5-7.5.

Ever wonder how a blind person knows when to stop wiping?

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I spoke with a used truck salesman. To my surprise he was leading me to Eaton Fuller drivelines or transmissions with only a .7 overdrive. His recommendation was 300 or 350 E7 or EM7 with a 9 or 10 speed, a 3.86 to 3.58 rear and LP 22.5 tires. He said I should run the engine about 1400 rpm.

I specified that I wanted excellent fuel mileage. The run is mostly level with no real big hills.

Those with experience care to comment?

You'll never go wrong by doing right.

Who do you call when the lawmakers ignore the law?

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I spoke with a used truck salesman. To my surprise he was leading me to Eaton Fuller drivelines or transmissions with only a .7 overdrive. His recommendation was 300 or 350 E7 or EM7 with a 9 or 10 speed, a 3.86 to 3.58 rear and LP 22.5 tires. He said I should run the engine about 1400 rpm.

One thing to remember, when buying used, the salesman will explain to you that the best thing for you is the truck that is on his lot! If he has to go find you something else where then he is not moving his inventory. Or there is a good chance that he has a line on a trade in fleet of a certain spec, say a fleet of EM7 300hp or E7 350hp trucks with 9 & 10 speeds that he can buy really right, mark up $9,000.00 and still make you a good deal. This salesman might be looking out for you, but when I was selling trucks, I perferred selling used, because the profit margin is much higher for the dealer and saleman. This coming from a former Mack salesman.

T.

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