gear questions
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Elder User
Joined: Sep 2003
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From: Myrtle Point, Or
gear questions
Ok, I was thinking of changing my gears sometime, just not sure what yet.
But here is what my question is.
On my '89 bronco, is the front gear, the same ratio as the rear?
If so, how do I find out that the ratio is, other then taking the cover off.
BTW, I have a c6 3 speed in it.
But here is what my question is.
On my '89 bronco, is the front gear, the same ratio as the rear?
If so, how do I find out that the ratio is, other then taking the cover off.
BTW, I have a c6 3 speed in it.
Hotshot
Joined: Jul 2002
Posts: 14,285
Likes: 12
From: Bend,OR
there should be a tag on the rear diff that tells the ratio. the front is usually one diget off. for instance the rear being 3.55 and front 3.54. if you plan on regearing take into concideration what size tires you plan to run in the future sense you have a 3 speed 4.10's would be a good safe choice with 33's or even 35's maybe.what size engine you running? just remember you must do both gears the same otherwise you cant use 4x4
late
late
Freshman User
Joined: Oct 2003
Posts: 38
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From: Jackson Hole, Wyoming
Keep the carrier in mind
On a dana 44 TBS front, if you go over 3.73 in the front, you have to change the carrier also. (which can be expensive)
I went from a 3.54 front to a 4.09 and got a precision gear power loc carrier at the same time. In the back, you can use the stock open carrier with 4.10 gears but while you've got it out, it's best to toss an EZ-locker in there for another 200 bux. Whatever gear ratio you choose, just remember the front carrier will have to change also if you go big.
stock carrier = 3.73 and under
New carrier = 3.92 and over
I wouldn't go bigger than 35's or 36's with stock axles, so 4.10's will do you fine if you stay on the road mostly. If you want to do some crawling, 5.13 is the largest matched set you can get. You can go up to 5.88 in the back but I think the closest front ratio to that is still not close enough for safe pavement use.
I went from a 3.54 front to a 4.09 and got a precision gear power loc carrier at the same time. In the back, you can use the stock open carrier with 4.10 gears but while you've got it out, it's best to toss an EZ-locker in there for another 200 bux. Whatever gear ratio you choose, just remember the front carrier will have to change also if you go big.
stock carrier = 3.73 and under
New carrier = 3.92 and over
I wouldn't go bigger than 35's or 36's with stock axles, so 4.10's will do you fine if you stay on the road mostly. If you want to do some crawling, 5.13 is the largest matched set you can get. You can go up to 5.88 in the back but I think the closest front ratio to that is still not close enough for safe pavement use.
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
A little math for the calculating....
MPH (highway speed) x gear ratio (rear end) x 336 / tire diameter
Gives you engine RPM.
or
If you have a transmission with overdrive...
MPH (highway speed) x gear ratio (rear end) x overdrive ratio (usually about .73-.75) x 336 / tire diameter
Gives you engine RPM
Example:
60 (mph) x 3.55 (rear end ratio) x 336 / 31 (diameter in inches) = 2308.
And if you think OD doesn't make much difference:
60 x 3.55 x .75 x 336 / 31 = 1731
The engine RPM should be at or just below your engine's power band 2000-2800 on average for a SB V8. (Some will argue a little less or a little more).
The gearing front and rear should remain very very close. Ford geared the front .01 different in an effort to get the front end to pull just a touch when running in 4WD. Hence, as Kem stated, the 3.54 front and 3.55 rear.
MPH (highway speed) x gear ratio (rear end) x 336 / tire diameter
Gives you engine RPM.
or
If you have a transmission with overdrive...
MPH (highway speed) x gear ratio (rear end) x overdrive ratio (usually about .73-.75) x 336 / tire diameter
Gives you engine RPM
Example:
60 (mph) x 3.55 (rear end ratio) x 336 / 31 (diameter in inches) = 2308.
And if you think OD doesn't make much difference:
60 x 3.55 x .75 x 336 / 31 = 1731
The engine RPM should be at or just below your engine's power band 2000-2800 on average for a SB V8. (Some will argue a little less or a little more).
The gearing front and rear should remain very very close. Ford geared the front .01 different in an effort to get the front end to pull just a touch when running in 4WD. Hence, as Kem stated, the 3.54 front and 3.55 rear.
Last edited by greystreak92; Oct 3, 2003 at 12:43 AM.
Thread Starter
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Elder User
Joined: Sep 2003
Posts: 533
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From: Myrtle Point, Or
so the .01 in the gears doesn't hurt anything, thats good. I don't know what i habe now, the tag just has a bunch of numbers and letters, nothing coming out to a gear ratio. I'll keep huniting, maybe the vin will do the trick.
Tuned
Joined: Nov 2001
Posts: 281
Likes: 1
From: Back in Central Texas
This should help you decide what gear ratio to use with the size of your tires.
http://www.tennessee4x4.com/trailrun...atio-guide.htm
DG808
http://www.tennessee4x4.com/trailrun...atio-guide.htm
DG808
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Elder User
Joined: Sep 2003
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From: Myrtle Point, Or
Originally posted by Doorgunner808
This should help you decide what gear ratio to use with the size of your tires.
http://www.tennessee4x4.com/trailrun...atio-guide.htm
DG808
This should help you decide what gear ratio to use with the size of your tires.
http://www.tennessee4x4.com/trailrun...atio-guide.htm
DG808
BTW, in your sig, it says bonco, not bronco-lol
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Tuned
Joined: Nov 2001
Posts: 281
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From: Back in Central Texas
Boy am i red in the face, thanks for pointing that out, I updated my sig very late lastnight (early mornin). Us army guys aren't always as literate as we'd like to be at 4 am. LOL
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Elder User
Joined: Sep 2003
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From: Myrtle Point, Or
Originally posted by Doorgunner808
Boy am i red in the face, thanks for pointing that out, I updated my sig very late lastnight (early mornin). Us army guys aren't always as literate as we'd like to be at 4 am. LOL
Boy am i red in the face, thanks for pointing that out, I updated my sig very late lastnight (early mornin). Us army guys aren't always as literate as we'd like to be at 4 am. LOL
No prob, didn't think u wanted everyone to think u had a bonco!!!
I don't think anyone is really good at that time of night, not even me, and thats when I work-lol
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