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Feb 20, 2011 | 05:20 PM

theblalock3

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gears

Ford is claiming the same gas mileage whether the gears are 3:55 or 3:73's. Real world,is this correct?

Feb 20, 2011 | 08:52 PM

tvsjr

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Most likely... depends on your driving habits. If you spend lots of time at higher RPMs (say you like driving at super-legal speeds on the highway) then the 3.73s will hurt you a bit as you start to get outside the powerband of the motor. However, the 3.73s will get the vehicle moving a bit easier in stop-and-go or trailering situations. I would expect to see less than 1MPG difference in most any situation.

Feb 20, 2011 | 10:21 PM

Matts72

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From: Montana Territory

I doubt it would change much if any. The 6 speed transmission really makes up for a lot, but the actual difference between 3.55 and 3.73 is seen only when towing/hauling. The motors have a ton of technology to make less power when you don't need it and the working range is very wide with all the motors because of the technology.

Feb 20, 2011 | 11:28 PM

Deluxe05

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From: Denver, Co

Rather than repeat, I will simply point you to a rather recent post with a similar topic:

https://www.ford-trucks.com/forums/1...ml#post9938941

Feb 21, 2011 | 06:28 AM

tseekins

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From: Maine, Virginia

Quote:

Originally Posted by Deluxe05

Rather than repeat, I will simply point you to a rather recent post with a similar topic:

https://www.ford-trucks.com/forums/1...ml#post9938941

Excellent post sir. Your reference post was spot on. I was trying to explain that to my salesman quite some time ago and he just didn't get it. I think it's the # of turns of the drive shaft vs. the one turn of the rear wheels that messed him up.

Feb 21, 2011 | 08:26 AM

Fred Smedley123

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There are many issues to consider such as actual weight of the vehicle & are you towing & what is your intended application. I would Image weight could vary 1800-2000 lbs between a regular cab 2 wheel to a screw 4 wheel. . What tire are you ordering. My 2011 F-150 with with the 255-18's running a 3.55 gear tacks 1700 in 6th @65. My 04 F-250 with 3.73's running the stock XL 16" tire/wheel was running 1750-1800 @ 65 with the 4 auto. I got the 3.55 as I have the lightest truck I could buy and a 5.0 which has big HP-torque #'s for a light truck. Even though I am towing 2500lbs all the time their are six gears to put me in the powerband I want. In town empty I am getting 18 and 21-23 highway holding @65.

Feb 21, 2011 | 10:35 AM

Seaark18

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From: Martin, OH

Good Info! I'm trying to decide between a 4x4 5.0 screw FX4 or 5.0 screw Lariat. The FX4 obviously comes only with 3.73's, while I could get 3.55's on the Lariat. I occasionally tow 5-6k lbs, but most driving is unloaded, and on the highway between 65 and 80 depending on what state I'm in. You guys think there would be little to no difference in mpg? Thanks!