Axle Ratios

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Nov 16, 2004 | 09:42 PM

BRETDILLION

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Axle Ratios

'98 F-150 4X4, street driven. What happens if I change the ratio of the rear axle without changing the front? Will this cause damage? Thankyou.

Nov 16, 2004 | 10:05 PM

F150dana44

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if you were to put it in four wheel drive the transfer case damaged and/or the differential with the lower gears would be put underalot of stress. That being said it is ok to run gears that are .01 different, some people say it is ok to even have .05 difference in gears

Nov 16, 2004 | 10:27 PM

Indybroncoman

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From: North Carolina

I once ran a 3.50 rear and a 3.54 front but that was only until I could get a front diff with 3.50 gears. I was desperate and broke and even used it in 4WD in the snow. Having said that, I don't recommend it. I'm not sure at what point it no longer becomes safe but I'd hate to learn the answer the hard way.

Nov 17, 2004 | 08:39 PM

SoCalDesertRider

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From: USA

3.50 and 3.54 is fine in a truck with part-time 4wd that is used properly (only on slippery surfaces, never on pavement). What you don't want is 3.50 and 3.73...

Nov 17, 2004 | 10:29 PM

ivanribic

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From: Spokane, WA

If you do run slightly different gears front and back you really should run the numerically lower gears up front. For instance, if you were running 4.10's and 4.11's (some Fords came stock this way) you'd want the 4.10 up front and the 4.11 out back. This causes the front to turn just slightly faster than the rear so the truck is really being pulled a little by the front end when in 4x4. If you reverse this and the rear turns faster it can cause you to lose control as the back tires are spinning faster than the front. If the surface you're on is slick enough though, you really won't notice a difference.

Nov 19, 2004 | 07:53 PM

kspilkinton

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From: South Kitsap County, WA

OK, Ivan, so what was Ford thinking when they made the 3.54 Dana-44 front and 3.50 9" rear? Just had to throw that one in there.... Ford made that combo on F150's for several years-- at least as early as '78 through the cross over to the 8.8 in '86