gear swap

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Aug 29, 2021 | 07:19 PM

sbraatz

Thread Starter

Mountain Pass

Joined: Jan 2007

Posts: 182

Likes: 31

From: San Jose, CA

gear swap

Thinking about changing the 410 gears for 373 on my 96 ZF 5 speed dually. I'm not doing any big towing any more. I'm just hoping to get better mileage on the highway all while lowering the rpms. Any suggestions? What cost would I be looking at?
Thanks to you guys in advance.
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Aug 29, 2021 | 09:39 PM

Edgethis

Lead Driver

Joined: May 2009

Posts: 6,815

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From: Tobyhanma, PA

Quote:

Originally Posted by sbraatz

Well, gears alone are 200-250. A good bearing and shim kit is another 150-200. Just regeared and added a truetrac in mine a few months back. Used motive gears and a kit with tinken bearings.

Aug 29, 2021 | 10:39 PM

96 OBS

Laughing Gas

Joined: Oct 2019

Posts: 949

Likes: 109

From: Fowler Colorado

Mine had 3.55s on it and it was perfect for Highway driving. And I could tow 10k without hesitation. Fairly modified truck tho. Definitely check out @Edgethis rear end build great info

Aug 30, 2021 | 02:47 AM

Hit Man X

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Joined: Sep 2002

Posts: 9,548

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From: North Texas

I would do 3.55:1. Check RPM in fourth with that ratio. Prob around 2600 at 70mph.

Aug 30, 2021 | 12:49 PM

sbraatz

Thread Starter

Mountain Pass

Joined: Jan 2007

Posts: 182

Likes: 31

From: San Jose, CA

Thanks for the info. Where would I go for the parts?

Aug 30, 2021 | 01:41 PM

sbraatz

Thread Starter

Mountain Pass

Joined: Jan 2007

Posts: 182

Likes: 31

From: San Jose, CA

Any guess on what sort of improvement I could see on mpg's with the gear swap? That way I could figure out the payback cycle.

Aug 30, 2021 | 05:06 PM

Hit Man X

Lead Driver

Joined: Sep 2002

Posts: 9,548

Likes: 2,034

From: North Texas

My dually does about 17mpg freeway going 65mph. 16s if I go 70. ECLB model. Near stock size tires at 30.5" not sure if dropping to a 3.73:1 will yield much for economy gains to offest the cost onset.

I see a fair amount of Superduty in the yards now that are gassers. At times you will find a clapped 6.0. Maybe could get lucky and find a 3.73:1 out there if that is what you want. But unsure if the 10.5" gearset fits. Plenty of 3/4 ton 10.25" out there now.

Randy's has always proven good for parts.