'68 Chevy 4x4 Axle Swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ol' Chevy · 05-29-2013, 05:57 PM

Howdy,
I'm getting ready to swap out the original axles under my pickup for a Dana 60 (rear) and a Dana 44 (front). Currently the rig has 4.56:1 gears in it. The Dana 60 I'm buying has 4.10's, and I think I have a lead on a Dana 44 with 4.10's. I'm expecting a little quieter ride, and hoping for a boost in gas mileage. Is anyone running 4.10's with stock tires, and if so, would you reccomend that gear ratio, or would I get significantly better gas mileage with 3.73 gears? The reason behind the 4.10's is mostly availability. No yards around here have 3/4 ton diff's with 3.73's

**Stocker** · 05-29-2013, 08:59 PM

Welcome from NorCal!

I have 4.10s in my '72 K20, with 33/12.50-16.5s that are just a tick taller than the original 7.50-16s. It's OK on secondary roads at 55 mph but you don't really want to go much faster... 70 on the freeway is pushing it pretty hard. Depends on how you'll be using the truck but if it sees a lot of highway miles I'd try for taller gears, taller tires, or an overdrive unit or overdrive tranny. 4.10s are great for a workhorse that doesn't spend much time on the open road, especially freeways.

**americanmusc1e** · 05-30-2013, 11:34 AM

http://www.grimmjeeper.com/gears.html

use this as a handy tool to figure out how much it's going to change for you.

4.10's will definitely be better than 4.56, but if you do more driving than hauling i'd recommend 3.73's or 3.55's.

some of it depends on the intended use of the truck and what engine/transmission you have. my 4x4 is going to have 3.73 gears with 35" tires, which is equivalent to 3.23's with stock tires. I have a 383 small block that has a very usable power band though and i'm not planning on pulling anything with it.

Ol' Chevy · 06-03-2013, 12:41 PM

Thanks for the info. I do most on my driving on county roads or highways, usually from 45-60 MPH. I want to be able to haul a cord of wood or a camper, but I also want to be able to take said camper to Idaho or Montana without breaking the bank. I picked up a Dana 60 with 4.10's the other day. If I can find a Dana 44 front with 3.73's I'll regear the rear to match, otherwise I'll probably just stay with the 4.10's.

05-29-2013, 05:57 PM	#1
Ol' Chevy Registered User Join Date: May 2013 Location: Elma, WA Posts: 7	'68 Chevy 4x4 Axle Swap Howdy, I'm getting ready to swap out the original axles under my pickup for a Dana 60 (rear) and a Dana 44 (front). Currently the rig has 4.56:1 gears in it. The Dana 60 I'm buying has 4.10's, and I think I have a lead on a Dana 44 with 4.10's. I'm expecting a little quieter ride, and hoping for a boost in gas mileage. Is anyone running 4.10's with stock tires, and if so, would you reccomend that gear ratio, or would I get significantly better gas mileage with 3.73 gears? The reason behind the 4.10's is mostly availability. No yards around here have 3/4 ton diff's with 3.73's

05-29-2013, 08:59 PM	#2
Stocker 20' Daredevil (Ret) Join Date: May 2003 Location: Jefferson State Posts: 13,728	Re: '68 Chevy 4x4 Axle Swap Welcome from NorCal! I have 4.10s in my '72 K20, with 33/12.50-16.5s that are just a tick taller than the original 7.50-16s. It's OK on secondary roads at 55 mph but you don't really want to go much faster... 70 on the freeway is pushing it pretty hard. Depends on how you'll be using the truck but if it sees a lot of highway miles I'd try for taller gears, taller tires, or an overdrive unit or overdrive tranny. 4.10s are great for a workhorse that doesn't spend much time on the open road, especially freeways. __________________ - Mike - 1972 K20 LWB 350/350/205 RIP El Jay

05-30-2013, 11:34 AM	#3
americanmusc1e Senior Member Join Date: Jan 2009 Location: Austin, TX Posts: 1,079	Re: '68 Chevy 4x4 Axle Swap http://www.grimmjeeper.com/gears.html use this as a handy tool to figure out how much it's going to change for you. 4.10's will definitely be better than 4.56, but if you do more driving than hauling i'd recommend 3.73's or 3.55's. some of it depends on the intended use of the truck and what engine/transmission you have. my 4x4 is going to have 3.73 gears with 35" tires, which is equivalent to 3.23's with stock tires. I have a 383 small block that has a very usable power band though and i'm not planning on pulling anything with it. __________________ -- Josh Instagram: @americanmusc1e OLD SKOOL-- 1970 C10. 454/Th400/3.07 posi Build Thread FARM TRUCK----1949 Chevrolet 3800 Power Wagon Hauler Build Thread 1999 4wd OBS Tahoe - daily. DM me if you can't see photos i posted

06-03-2013, 12:41 PM	#4
Ol' Chevy Registered User Join Date: May 2013 Location: Elma, WA Posts: 7	Re: '68 Chevy 4x4 Axle Swap Thanks for the info. I do most on my driving on county roads or highways, usually from 45-60 MPH. I want to be able to haul a cord of wood or a camper, but I also want to be able to take said camper to Idaho or Montana without breaking the bank. I picked up a Dana 60 with 4.10's the other day. If I can find a Dana 44 front with 3.73's I'll regear the rear to match, otherwise I'll probably just stay with the 4.10's.



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