1986 bronco gear ratio

[T2HUFF]

what gear ratio came standard on 86 bronco 302? i read 3:45 with optional 3:73. can anyone confirm this?

 

[Rons beast]

Hey T welcome,

the most likely is the 3:45...However, and its a big However, A vehicle that old could have the ratios /axels changed.  The best way to determine ratio is to count turns of the driveshaft per 1 turn of the rear wheel.  Or better count the gears themselves. 

Good Luck.

 

[T2HUFF]

okay, and thank you very much, i was just wondering since i found it odd they only made it in 86.. and was hoping it was a typo on the page, this is where i got it from http://www.automobile-catalog.com/list-ford_usa.html kinda cool facts if  anyone wants to learn more on there trucks

 

[Rons beast]

If they only made it one year, even more reason to think that somewhere down the road things may have been changed.

I have to ask ...Why do you need to know? 

 

[T2HUFF]

since i was doing a front axle swap to fix my accident, but ended up just getting a front and rear axle haha

 

[miesk5]

yo,

Brochure, 86 Bronco

Source: by Ford via http://www.supermotors.net/registry/media/795589

see http://www.supermotors.net/registry/media/795596_1

Ford yaks about Heavy Duty Front Suspension/Snow Plow Package and mentions;

...package include HD front suspension with 3.50 or 3.54 axle ratio...

For Original as built info;

Door Jamb Label (Certification Label, also referred to as the Patent Plate, Data Plate & the Warranty Plate) pic in an 87 5.0

Source: by ChipW at http://www.supermotors.net/registry/media/915111

Shows rear code 19

Differential AXLE CODES REAR by Keith L (TTB Blows, Bling-Bling) at http://web.archive.org/web/20020220012159/http://90bronco.homestead.com/axlecode.html

REGULAR: (Regular means "open" diff in this context)

13 4.11

14 3.00

16 3.50

18 3.08

19 3.55

LIMITED SLIP:

H3 4.11

H4 3.00

H5 4.10

H6 3.50

H8 3.08

H9 3.55

==============

Ford built our Broncos & other 4x4 trucks & vans with a numerically lower front gear ratio in the front Dana 44 than the rear so that off-road steering is enhanced. A Bronco built with 3.55 rear ratio would have a 3.54 ratio in the front Dana 44; or; 3.08 in the 8.8 & 3.07 in the Dana 44; or 4.11 in the 8.8 & 4.10 in the Dana 44, etc.

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Following was in my MS WORD Notes and the source, Randy's Ring & Pinion has removed it from their current web site; The gear ratio in the front of a four wheel drive has to be different from the front so the front wheels will pull more. There have been many different ratio combinations used in four-wheel drive vehicles, but not so that the front will pull more. Gear manufactures use different ratios for many different reasons. Some of those reasons are: strength, gear life, noise (or lack of it), geometric constraints, or simply because of the tooling they have available. I have seen Ford use a 3.50 ratio in the rear with a 3.54 in the front, or a 4.11 in the rear with a 4.09 in the front. As long as the front and rear ratios are within 1%, the vehicle works just fine on the road, and can even be as different as 2% for off-road use with no side effects. point difference in ratio is equal to 1%. To find the percentage difference in ratios it is necessary to divide, not subtract. In order to find the difference, divide one ratio by the other and look at the numbers to the right of the decimal point to see how far they vary from 1.00. For example: 3.54 ÷ 3.50 = 1.01, or 1%, not 4% different. And likewise 4.11 ÷ 4.09 = 1.005, or only a 1/2% difference. These differences are about the same as a 1/3" variation in front to rear tire height, which probably happens more often than we realize. A difference in the ratio will damage the transfer case. Any extreme difference in front and rear ratios or front and rear tire height will put undue force on the drive train. However, any difference will put strain on all parts of the drivetrain. The forces generated from the difference have to travel through the axle assemblies and the driveshafts to get to the transfer case. These excessive forces can just as easily break a front u-joint or rear spider gear as well as parts in the transfer case. by Randy's Ring & Pinion