Help!!!
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New User
Joined: Feb 2006
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Help!!!
I have two issues.
I purchased a 2005 F-350 4X4 SWB dulley with 4.10. I would like to change it to 3.73 to increase my milage in town and on the hwy. I am wondering if anyone can give me some idea how many mpg I can expect? If you have made this swap please give me the +/- of doing it.
The other question is, my truck has the integrated trailer braking system with the four AUX power switches next to it. I am wanting use the switches, but I cannot find any information my owners manual about the circuts. If you can tell me how to access them I would really appreciate the help.
I purchased a 2005 F-350 4X4 SWB dulley with 4.10. I would like to change it to 3.73 to increase my milage in town and on the hwy. I am wondering if anyone can give me some idea how many mpg I can expect? If you have made this swap please give me the +/- of doing it.
The other question is, my truck has the integrated trailer braking system with the four AUX power switches next to it. I am wanting use the switches, but I cannot find any information my owners manual about the circuts. If you can tell me how to access them I would really appreciate the help.
Posting Guru
Joined: Jul 2005
Posts: 1,617
Likes: 4
From: Denver, Co
This should help you on the second part of your question:
https://www.fleet.ford.com/truckbbas/non-html/Q117.pdf
https://www.fleet.ford.com/truckbbas/non-html/Q117.pdf
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We are happy you have chosen the best source for Fords.
Enjoy FTE....and
JOIN CLUB FTE -SUPPORT THE FORUMS!
…..See you on the boards.
Fleet Mechanic
Joined: Jul 2005
Posts: 1,800
Likes: 52
From: Southern Colorado
The expense of buying and installing two sets of ring/pinion gears will likely not be offset by the fuel savings, unless you drive this truck a many miles. Resale (as a tow rig) won't be helped by 3.73s.
If you saw a solid 2 mpg gain across the board, I'd be surprised - so I'd use that as an optimistic figure. If it now gets 11 mpg, and would get 13 mpg with 3.73s, and you drove 15K miles/year, you'd save $524/year in gas at $2.50/gallon.
If you saw a solid 2 mpg gain across the board, I'd be surprised - so I'd use that as an optimistic figure. If it now gets 11 mpg, and would get 13 mpg with 3.73s, and you drove 15K miles/year, you'd save $524/year in gas at $2.50/gallon.
Postmaster
Joined: Jan 2005
Posts: 2,753
Likes: 3
From: Phenix City, AL
The 3.73's won't get you better mileage in these trucks. It puts the engine too low in the RPM range and the engines lug and the tranny shifts on small inclines or head winds.
It's a 4x4 so figure on spending around 1100 - 1600 for the gear swap. Do the math, it ain't worth the expense.
Lastly, look at Monsta's sig:
"Choosing gears for economy is like getting a Diet Coke with a Whopper Meal"
I still love that one.
It's a 4x4 so figure on spending around 1100 - 1600 for the gear swap. Do the math, it ain't worth the expense.
Lastly, look at Monsta's sig:
"Choosing gears for economy is like getting a Diet Coke with a Whopper Meal"
I still love that one.
