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Old 04/19/18, 04:09 PM   #16
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El Monte CA
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Originally Posted by blubuckaroo View Post
You know how shifting out of from 4WD to 2WD the transfer case sometimes gets stuck and backing up helps?
That used to happen to me when I had 3.50 rears and 3.54 fronts. The rear was crowding the front.
Now I have 4.11 rears and 4.09 fronts. That sticky transfer case issue hasn't happened since the gear swap. I think it's because the front is turning faster than the rear.
Mine was better with the same swap too.

I'd pull the cover on the front gear set and verify the gear count. I would expect if the gears were that far off you would have a hell of a time shifting it.

1974, stock 302, C4, BFG KM2 33x12.5x15, 8in rim, detroit rear, trutrac front 4.11 gearing, Warflairs,2.5" lift, chevy disc conversion, Hydraboost, owned since Christmas Eve 1977
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Old 04/19/18, 05:57 PM   #17
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Did he ever confirm that they really are 3.73? That just isn't a gear ratio that you normally find in a Bronco. Someone had to go out of there way to do it, if that is really what it is. I'm guessing that with backlash it just wasn't counted correctly.

"She's built like a steakhouse but she handles like a bistro"-Zapp Brannigan
“How hard can it be?”-Clarksonius 4th century BC.
Full throttle, it either solves the problem or ends the suspense.
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Old 04/19/18, 07:07 PM   #18
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Originally Posted by garberz View Post
I think that was what the marketing dept. came up with. With Ford making the rear, and Dana making the front, that's the reason they're slightly different. Mine's 4.56 up front, 4.57 out back.

There are actually 4.56 and 4.57 ratio ring and pinion gear sets made for the Ford 9 inch.

4.56 are 9 teeth on the pinion and 41 on the ring gear,

4.57 are 7 teeth on the pinion and 32 on the ring gear.

... I've got skills, ingenuity and no regard for maintaining any kind of historical preservation or authenticity...My Dad called that sick and wrong
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Old 04/19/18, 07:48 PM   #19
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Originally Posted by sykanr0ng View Post
There are actually 4.56 and 4.57 ratio ring and pinion gear sets made for the Ford 9 inch.

4.56 are 9 teeth on the pinion and 41 on the ring gear,

4.57 are 7 teeth on the pinion and 32 on the ring gear.
That’s interesting, I wonder what other ratio’s are matching between Ford and Dana?


EFI, OBDII, 5.0, C4, AtlasII 3.8. 4.56's, Detroit's, 35's, Duff Long Arms, 5.5" coils w/adjustable mounts. 3" suspension lift.
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Old 04/20/18, 04:22 PM   #20
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For a week or two I had 33" tires on the back and 28" tires on the front of my F-150. That's about the equivalent of 4.10 gears in the front and 3.54 in the rear. During that time I got stuck on a muddy hill and needed to use 4WD. The truck was almost unsteerable. The different ratios meant that always both tires on one axle were sliding. Which axle was sliding would switch back and forth, and the net effect was that the truck pretty much went where it wanted regardless of where I pointed the tires. I was able to get up the hill and shift back into 2WD. But I proved, at least to myself, that mismatched ratios don't work on slippery surfaces either.

edit: The purpose of the mis-matched tires was to test how the truck would do with taller tires. I was going to lift it and put 33s on, but wanted to know if I needed to change the 3.54 gears. The 33s didn't fit on the front without a lift, but they did fit on the rear. So I changed the rear tires and drove it for a couple weeks, including a trip to tow a small farm tractor. I decided that the 3.54 gears were fine with the 33s and I didn't need to regear. So I put the 28s back on until I did lift it and could put 33s on both ends. I knew I couldn't use 4WD with the mis-matched sizes. But when I couldn't get up the hill, and knew that with it as slippery as it was it would never cause any bind problems I did it. It got me up the hill, didn't cause any problems (other than handling!) and gave me first-hand experience how bad that could be!

Last edited by Nothing Special; 04/21/18 at 06:18 AM..

'71 Bronco, 302, NV3550 5 spd, Atlas 4.3:1, 4.10:1, Detroit rear, 33" BFG AT Build Thread
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Old 04/20/18, 05:02 PM   #21
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That's brother and I took his Toyota out in the snow/ice when it had the 4.88/5.29 gear mismatch and it was the same thing. You couldn't go straight if you wanted to, with or without the ARB's locked. It was like driving a shopping cart, loaded with bowling balls down a flight of stairs...scary at best, downright dangerous at worst. I'm not sure how those mud/sand guys make it work, but my guess is that they're carrying/skimming their front tires as much as possible with 1600 HP and comp cut Boggers or paddle tires.

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Old 04/20/18, 11:59 PM   #22
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I test drove a fullsize Bronco with mismatched gears. It was very clear within a few feet in 4wd that there was a serious problem. The term "Bucking Bronco" fit very well. Once stopped the drivetrain was so bound up I had a hard time getting it back in 2wd to drive it back. Then the seller tried to convince me that when you put the t-case in 4wd you are supposed to unlock the front hubs.

That Bronco didn't follow me home. Mismatched gears in 4wd is a no no.

-Rough 73, cut, 400, np435, d20, 35s. Workin' on it.
-90 xlt, 351w, e4od, bw1356, 35s.
El Kabong is a cartoon horse from when I was a kid in the the 60s. No bong was used in the selection of this user name.
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