Two different ratios
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Two different ratios
I need a new rear end for my 78 f150 4x4 with a 3.50 ratio. But I've been looking around for awhile and have found 3.55 and 3.54(?) ratios and I was wondering if that difference would hurt or wear anything if 4wd was used on road i.e. in snow and ice?
Also I'm not sure of my front ratio but my door tag said 3.50 for axle code.
Also I'm not sure of my front ratio but my door tag said 3.50 for axle code.
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Joined: Apr 2004
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Your truck has a 9" Ford axle, right? What axles are you looking at with 3.55 or 3.54 ratios? You should be able to rebuild or buy a 3.50 9".
If your front axle is 3.50 or close, the change to 3.55 or 3.54 will be ok under the condtions you note.
You're not going to make a 5/8s out of it by putting a 3/4 ton axle in the back....I hope.....???
If your front axle is 3.50 or close, the change to 3.55 or 3.54 will be ok under the condtions you note.
You're not going to make a 5/8s out of it by putting a 3/4 ton axle in the back....I hope.....???
Cargo Master
Joined: Feb 2006
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From: North Pole, Alaska
Your rearend is a Ford 9 inch with a ratio of 3.50. Your front axle is a Dana 44 with a 3.54 ratio, a totally different manufacturer. The 3.54 is close enough to not have much effect with wrapup and binding. A figure that has been mentioned in the forums has been 3% difference and under. If somebody makes a 3.55 ratio, you could use that, but the original Ford ratio was 3.50.
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I'm still searching for the right gear ratio. I found a 9 in out of a 1980 f100 with the gears I need and 31 spline. I was wanting to know if it would bolt up in my '78?
I know that some of those f100s came with a small lug pattern and some with the larger. I just was wondering if the spring perches and width were the same.
I know that some of those f100s came with a small lug pattern and some with the larger. I just was wondering if the spring perches and width were the same.
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