Rearend Gear Ratio vs Fuel Mileage -Diesel Engine

[Montana_4911]

Hello Gang,

OK, I don't mean to wear this one out, but I need some real good input, and appreciate anyone's help.

I am about to purchase a Ford F-350 Diesel 6.0 with an automatic transmission and Tow Boss and my rear gear ratio options are 4.10 OR 4.30 ( Tow Boss Ford Option ).

I will pull 5th wheel's of about 15,000 pounds for a transportation company. My top speed will be 65 MPH and go about 125,000 miles a year, and be flat land or mountains.

FYI - 1 mile per gallon difference equals $ 3,700 savings or loss in fuel costs, however power and control is important on the hills.

My mechanic says the higher the gear ratio, the less stress on the power train.

My questions :

1 > What is the rear end ratio of your diesel truck

2 > What fuel MPG do you get unloaded.

3 > What is your weight of your load and what is you MPG with the load.

4 > Any other suggestions

Thanks much again,

[H. John Kohl]

1. 3.73
2. 19 to 21 mpg still breaking in only 30K miles
3. 23000 truck and trailer actually 22800
4. If your pulling 15000 trailer, I would go with the tow boss 4.3 to take the stress off the truck. I think your out there to get down the road especially in the hills more than to same money. One commercial hauller with an 2002 Ram 3500 pulling 20K cargo trailer wished he had the 3.53 so he could go faster. Traveling time was more important to him. You have the right questions now you have to answer them.
Good luck and tow safe.

[Montana Sky]

1. 3.73 Duramax w/ Allison 5 speed tranny
2. 19-22mpg empty
3. 20,985 CGVWR, average 12-14mpg towing
4. The 4.30 is going have better pulling torque but you will get less mpg compared to the 4.10 I would say it depends on who is paying the fuel bill, and are you being paid by the mile or the load. The 4.10 will not be as fast in the hills but will be able to handle the load and get a little better mileage doing it. Go with the one that your gut tells you to.

[Montana_4911]

Thanks Gang,

And yes, I am paying the fuel bill. I guess if I saved 2 MPG per year, I could buy a new transmission and have a party with the $ 7,400 savings.

[jackw87]

You should goto trailer life.com and check out trailer towing recommendationfor each vehicle and use what the manufactors recommend if 1 or t mpg is going to make up your mind the wind direction that much differant or more every body has there own requirments and if some one tells you that they are getting so and so for mpg and you get less with what the same vehicle you will be angry with them every body drives differant so go with your gut feeling

[Montana_4911]

OK, Thanks much