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May 5, 2009 | 12:41 AM

#16

capn kirk

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Joined: Dec 2006

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its not good for the trans to run far out of gear ie 37 on 3.73s or 3.55s for too many miles it adds wear but i'm doing it for now on my gasser until i can get the $ to put some 4.30s on it and it really doesn't feel underpowered still spins em alot of other people

saving enough to do it all at once isn't bad at all just tryin to help you not feel discouraged

May 5, 2009 | 12:58 AM

#17

Furian

You Keep What You Kill

Joined: Dec 2006

Posts: 4,902

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From: Huntersville, NC

Quote:

Originally Posted by usmc161

When I talked to Randy's ring and pinion, they told me if I go to 4.10s (really 4.11) it would put the engine and transmission bacrk to stock rpms. I might go with the 4.30s but would going any lower will kill on the highway when not towing? Ford wants 700 for the rear gears and 400 for the fronts. With those prices the lift/tires might have to wait.

Are those Ford prices just for the gear sets or is labor included?

May 5, 2009 | 09:46 AM

#18

Ace!

Cargo Master

Joined: Nov 2004

Posts: 2,751

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From: So Oregon

What will end up happening if you go too low is your power will drop off at a certain mph/rpm. I don't know the torque curve of your truck, but say now you're going 70mph at 2000 rpms. If that's where your torque is best, and you've got some left for passing, you'll want to gear to put you in the same place on the torque curve. You can use some online calculators to find out, but you might need to know your tranmissions final ratio, as well as your tire size and gearing. You can play around with the gearing on the calculator to see where you'll be.

May 5, 2009 | 10:26 AM

#19

usmc161

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According to Randy's ring and Pinion web page the calculators all say go with 4.11s, its a couple rpms (under 20) difference. The 4.30s its around 50-60 rpm difference. So either way I go is find with me but I checked a different Ford dealer today and they quoted me 691 for the rear gears and 640 for the front gears, no bearings, crush nut, or shims. I found a place to install them for around 1000, which seeems reasonable. I don't want to damage the trans on summer trips with the bigger tires and no gears. I'm looking at aftermarket gears like yukon or percision gears, I don't know a lot about them just I've read some aftermarkets whine. Hope some one out there can steer me in the right direction or it will have to wait. Thanks

May 5, 2009 | 10:41 AM

#20

cartmanea

Lead Driver

Joined: Jun 2007

Posts: 6,757

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From: Corvallis, OR

With 37s, 4.30s will put you back to the stock ratio. I wouldn't bother going 4.10s since its not enough change, 4.30s will be the sweet spot.

31.6" x 4.30 / 3.73 = 36.42"

Going 4.56 would put your RPMs a little high at highway speeds, going 4.10s won't be enough change and your in-town mileage will suffer. 4.10s would also put more strain on the transmission.

May 5, 2009 | 12:19 PM

#21

EXv10

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Joined: Mar 2009

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From: Mt. Shasta California

Quote:

Originally Posted by usmc161

The aftermarket gears that whined probably weren't set up right. Also; there's hardly any difference between those 2 ratios

May 5, 2009 | 12:25 PM

#22

cartmanea

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Joined: Jun 2007

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From: Corvallis, OR

I got Yukon gears and they don't make any noise at all. If you set them up right they should be quiet, but there are cheaper gears that are difficult to set up.

May 5, 2009 | 02:31 PM

#23

usmc161

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Senior User

Joined: Nov 2005

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Thanks for the info guys. Just got off the phone with another Ford dealer and they qouted 458 rear and 464 front, but they could only get 4.10s. Looking for prices on 430 yukons now.......hope they are better than Fords.