Gear ratios...?

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Old Dec 23, 2005 | 09:38 PM
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Sarnan's Avatar
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Gear ratios...?

What are the actual ratios for each of the 6 gears on a '04 5.4L 3:55 r/e?
 
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Old Dec 24, 2005 | 09:13 AM
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You only have 4 gears.

1st. 2.84
2nd I don't remember
3rd 1
4th .7
 
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Old Dec 24, 2005 | 01:21 PM
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You have four forwards and a reverse so thats five gears. Haven't been following the new trucks too close to see what comes with what, but either tranny have the same ratios. Info from this post...

https://www.f150online.com/forums/sh...60#post1832360

Model: 4R70w
Type: Four speed + reverse and 70(x10)lbs of torque
Years: 94-96 Bronco, F150
..........97-02 Expedition, F150
..........04-06 F150
Engines: 300, 302, 4.2L, 4.6L, 5.4L
Display: PRN(D)21 w/ overdrive lockout switch
Fluid: Mercon V
Ratios:
1st 2.84:1
2nd 1.55:1
3rd 1.00:1
4th 0.70:1
Reverse 2.32:1
Trans code: U ('94-'03), A ('04-'06)

Model: 4R75E
Type: Four speed + reverse and 75(x10)lbs of torque
Years: 04-06 F150/ Mark LT
Engines: 5.4L
Display: PRN(D)21 w/ overdrive lockout switch
Fluid: ?
Ratios:
1st 2.84:1
2nd 1.55:1
3rd 1.00:1
4th 0.70:1
Reverse 2.32:1
Trans code: B ('04-'05), Q ('06), F ('06 Mark LT)

Adrianspeeder
 
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Old Dec 25, 2005 | 09:09 AM
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Thanks for the transmision info. Now, I have a novice question about rear-axle gear ratios. I understand that the trans gear ratio is the ratio of engine RPM to drive shaft rpm. In a rear axle, what is the meaning of 3:55 (my FX)? I noticed there are many axle options, 3:75, 4:10, etc. :santa:
 
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Old Dec 25, 2005 | 09:20 AM
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It's the ratio of the driveshaft RPM to the axle RPM. 3.55:1 means the driveshaft will rotate 3.55 times for every rotation of the axle.
 
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Old Dec 25, 2005 | 10:27 AM
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From: Dover AFB DE / Harrisburg PA
Yup what he said.

A lower number is a "taller" gear giving better highway milage, and a higher number is a "deeper" gear giving more off the line grunt.

Adrianspeeder
 
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