Narrowing a 68/newer 3/4 ton rear axle, anyone done it? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

buckroseau · 10-03-2014, 07:07 PM

Just like the title says.

68 or newer 3/4 ton rear axle for a 2wd truck. From my understanding the 68 and new axle is 1.5" wider than the 60-66 rear axle. I've got a 62 C20 and I'm wondering if this is an option.

I know narrowing axle's isn't anything new. I'm just wondering if there are any surprises where the splines couldn't be milled on the shafts after they were cut 3/4 of an inch on each one?

I would keep my rear axle but it is a 4.57 ring and pinion, and from what I have found out, lower ring and pinions are just not available. A 68 or new axle would get me into 3.60 or 3.70 option area. And rear C20 axles are fairly cheap to pick up.

Thoughts?

Thanks, Matt

**PGSigns** · 10-03-2014, 08:08 PM

You may find the extra width is not an issue. Several members have doe the swap on 60 to 66 trucks with out any problems. There are Several threads on it here. Here is a good one.
http://67-72chevytrucks.com/vboard/s...hlight=14-bolt
Jimmy

buckroseau · 10-03-2014, 08:13 PM

Quote:

Originally Posted by PGSigns

You may find the extra width is not an issue. Several members have doe the swap on 60 to 66 trucks with out any problems. There are Several threads on it here. Here is a good one.
http://67-72chevytrucks.com/vboard/s...hlight=14-bolt
Jimmy

I thought of that to, but these tires are right on the edge of touching the inner lip of the box side now.

I just thought maybe someone had already done it. I was curious as to if the axle shafts were straight, so that there was enough meat still there to cut an additional 3/4" of splines. Or, if they tapered off after the spline. I suppose a person could just shorten one side as well, and just cut 1.5" of spline in one shaft and leave the other side alone. It would save a lot of work and cost.

Matt

**Captainfab** · 10-03-2014, 11:17 PM

The Eaton HO52 in the C/K20's and C/K30's don't follow the same width differences as the C/K 10's. The Eaton under your truck should be 65.5" wide. There is a member here that put a 2000 14 bolt from a 3500 truck that measured 65.625" wide. Narrowing a full floater differential gets expensive since it is more time consuming than narrowing a semi-floater.

buckroseau · 10-03-2014, 11:25 PM

Quote:

Originally Posted by Captainfab

The Eaton HO52 in the C/K20's and C/K30's don't follow the same width differences as the C/K 10's. The Eaton under your truck should be 65.5" wide. There is a member here that put a 2000 14 bolt from a 3500 truck that measured 65.625" wide. Narrowing a full floater differential gets expensive since it is more time consuming than narrowing a semi-floater.

I'm all about easy. What years of the 3500 would work? And what was the ratio?

Matt

buckroseau · 10-03-2014, 11:47 PM

Quote:

Originally Posted by Captainfab

The Eaton HO52 in the C/K20's and C/K30's don't follow the same width differences as the C/K 10's. The Eaton under your truck should be 65.5" wide. There is a member here that put a 2000 14 bolt from a 3500 truck that measured 65.625" wide. Narrowing a full floater differential gets expensive since it is more time consuming than narrowing a semi-floater.

Would a 2500 work in that year as well?

Matt

**Captainfab** · 10-04-2014, 01:40 AM

That I do not know since I did not do the conversion I mentioned. Here is the thread for you to read thru.

http://www.67-72chevytrucks.com/vboa...olt+conversion

The link that PGSigns posted is a good one as well.

If you think you really need to have a differential narrowed, I wouldn't waste my time or money on an Eaton HO52. I would go with either a Dana 60 or a 10.5" 14 bolt. You might get lucky and find a Dana 60 from a '68-'72 C20. Then all you would have to do is move the trailing arm mounts to bolt it up to your '62

66Submarine · 10-03-2014, 11:40 PM

The common 14 bolt replaced the Eaton in 1973, not 1968. There were a few trucks with Dana rears as an option starting in '68.

Budman56 · 10-04-2014, 10:11 AM

what about a different offset in the wheel instead of modifying the rear end?

buckroseau · 10-04-2014, 11:27 AM

I'm going to look at a 14 bolt out of chevy 2500 after work today. I measured my 62 this morning and face to face was approx. 65" if the axle I'm looking at tonight is within an inch it will work.

Wheel offset would probably work but that requires new rims and there not cheap. It also doesn't address the gearing issue. Axle I'm looking at tonight has 3.73's in it. This axle is $300 and cutting and welding in brackets is easy for me.

Hopefully it is narrow enough!

**Captainfab** · 10-04-2014, 11:41 PM

I forgot to mention that a 14 bolt from a '73-'86 C/K30 or '87-'91 R/V3500 cab and chassis should be narrow enough

Mathew21 · 10-05-2014, 09:03 AM

Quote:

Originally Posted by Captainfab

I forgot to mention that a 14 bolt from a '73-'86 C/K30 or '87-'91 R/V3500 cab and chassis should be narrow enough

I was going to use C&C axle to replace mine in my 66 C20. But from what I remember when researching axle swaps the 14 bolt rear ends in 88-98? 2wd drive 3/4-1 ton trucks wms measures 65". I planned on making a trip to the Junk yard to measure one but I ended up going a different route.

buckroseau · 10-05-2014, 09:39 AM

My craigslist contact for the axle got busy yesterday and couldn't meet until Monday now. I'm still excited to find out the measurement. If it's in that 65" ball park I'm good to go.

I'm assuming the yokes are different as well, so I'm hoping I can talk him into cutting the driveshaft so I can get that as well.

Flathead Smith · 10-08-2014, 04:40 PM

One other option which I do not see mentioned is to find a third member from a newer Eaton ¾ (HO52) or 1 ton (HO72) and install it in your rear end. That’s what I did with my 65 C-20, of course it only took me from a 4:56 to a 4:11, but for me that was enough. I did have to cut some out of my drive shaft as the newer style Eaton was just a little longer.

Here is how I did it...you will need to scroll to the bottom.

http://67-72chevytrucks.com/vboard/s...d.php?t=534896

buckroseau · 10-08-2014, 10:41 PM

I ended buying an axle out of 1998 4wd c2500. It is the 65.625 so it should work perfect for what I'm doing. It was a 4.11 ratio, wanted to try a 3.73 but I will see how this works and if I need to change it at least I have options. This one was out of a running truck and it only cost me a $100 bucks.

Picking it up next Sunday. Once I tear into I will post up some pics of the fun.

Matt

buckroseau · 10-12-2014, 10:26 PM

Question for the axle guru's. This 65.625 axle that supposedly exists is kicking my ass. I picked up my $100 axle out of the 98 4wd c2500. Measured it up once it once it was out and it measures 66.5". Approx 1" to wide. This hub set up looks different than that 99 suburban I looked at last week. Still bought it since I told the guy I would take it even tho it may not work.

Any options to take a 1/2" off each side? Different drums or something?

Matt

**Captainfab** · 10-13-2014, 12:05 AM

I do not know of any easy way to shorten a differential 1". The 14 bolt under that other Burb had outboard drums. It is possible that switching the hubs, drums and backing plates could change the width, but I do not know for certain as I have not done that.

buckroseau · 10-13-2014, 12:08 AM

Yeah I didn't think so. Probably end up getting a few bucks back in scrap. Oh well.

This came out of a 98 C2500. From what I can gather on the internet it is a full floater dually axel. And it didn't come out of a dually.

Ozzy2013 · 10-13-2014, 12:14 AM

Im not sure but seem to remember someone making a disc conversion that made it narrower ans stop so much better.

66Submarine · 10-13-2014, 12:11 AM

As previously mentioned, you might also be able to use a cab and chassis dually axle, since they are narrower; I think something like 63".

If you are OK with 4.10's you can also just stick a 4.10 third member in the existing Eaton rear.

YMMV, but I recently realized I actually have 4.57's and a tach that reads slow in my C30 I drive everywhere. Have you driven the truck any at this point?

buckroseau · 10-13-2014, 01:42 AM

Quote:

Originally Posted by 66Submarine

As previously mentioned, you might also be able to use a cab and chassis dually axle, since they are narrower; I think something like 63".

If you are OK with 4.10's you can also just stick a 4.10 third member in the existing Eaton rear.

YMMV, but I recently realized I actually have 4.57's and a tach that reads slow in my C30 I drive everywhere. Have you driven the truck any at this point?

I'm ok with 4.10, was hoping for 3.73. Would the 3rd member from this 98 axle work in the existing Eaton rear end?

And yes, I've driven it a few miles. The clutch was a little week and so were the brakes. I guess after sitting 30 years you have to expect that. I replaced the dizzy last week with an HEI, new plugs, wires..that made a big difference. I replaced the manifold gaskets, had a healthy leak. The oil lines leading to the oil filter on the manifold were leaking, at least one was, so I ordered up new ones. I've also got a new master cylinder and slave coming this week.

After driving it a few feet I knew I wanted to gear it up. The thing is geared like a grain truck.

Matt

Mathew21 · 10-13-2014, 03:37 PM

buckroseau- Here's a post I made about axle widths awhile ago. Read the response #4.
http://67-72chevytrucks.com/vboard/s...d.php?t=620030

buckroseau · 10-13-2014, 03:59 PM

I ended up buying another axle this morning. It was in a running 97 c3500. This time I had the seller pull the wheels so I could measure. It was 65.625 exactly. Paid a little more but at least I have one now. Heading back over to the guys place tomorrow after work with my torch to cut it out. I'll take a few pics tomorrow night and post them up. This axle is not a full floater.

Mathew21 · 10-13-2014, 04:50 PM

Quote:

Originally Posted by buckroseau

I ended up buying another axle this morning. It was in a running 97 c3500. This time I had the seller pull the wheels so I could measure. It was 65.625 exactly. Paid a little more but at least I have one now. Heading back over to the guys place tomorrow after work with my torch to cut it out. I'll take a few pics tomorrow night and post them up. This axle is not a full floater.

Great, It sounds like you found what you needed.

buckroseau · 10-13-2014, 10:48 PM

Quote:

Originally Posted by Mathew21

Great, It sounds like you found what you needed.

It would seem so? I will take a few pics of the axle when I get it home tomorrow night.

Few pics from tonight. New oil lines showed up today so decided to throw those on real quick. When I replaced the exhaust manifold gasket and tipped the manifold away from the engine the old, dried up lines cracked and broke. Got the HEI tweeked a bit as well. This thing starts like it's fuel injected now.

Matt

10-03-2014, 07:07 PM	#1
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Narrowing a 68/newer 3/4 ton rear axle, anyone done it? Just like the title says. 68 or newer 3/4 ton rear axle for a 2wd truck. From my understanding the 68 and new axle is 1.5" wider than the 60-66 rear axle. I've got a 62 C20 and I'm wondering if this is an option. I know narrowing axle's isn't anything new. I'm just wondering if there are any surprises where the splines couldn't be milled on the shafts after they were cut 3/4 of an inch on each one? I would keep my rear axle but it is a 4.57 ring and pinion, and from what I have found out, lower ring and pinions are just not available. A 68 or new axle would get me into 3.60 or 3.70 option area. And rear C20 axles are fairly cheap to pick up. Thoughts? Thanks, Matt

10-03-2014, 08:08 PM	#2
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? You may find the extra width is not an issue. Several members have doe the swap on 60 to 66 trucks with out any problems. There are Several threads on it here. Here is a good one. http://67-72chevytrucks.com/vboard/s...hlight=14-bolt Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

10-04-2014, 01:40 AM	#7
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? That I do not know since I did not do the conversion I mentioned. Here is the thread for you to read thru. http://www.67-72chevytrucks.com/vboa...olt+conversion The link that PGSigns posted is a good one as well. If you think you really need to have a differential narrowed, I wouldn't waste my time or money on an Eaton HO52. I would go with either a Dana 60 or a 10.5" 14 bolt. You might get lucky and find a Dana 60 from a '68-'72 C20. Then all you would have to do is move the trailing arm mounts to bolt it up to your '62 __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE Last edited by Captainfab; 10-04-2014 at 01:46 AM.

10-03-2014, 11:40 PM	#8
66Submarine Registered User Join Date: Sep 2012 Location: Dallas, GA Posts: 1,497	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? The common 14 bolt replaced the Eaton in 1973, not 1968. There were a few trucks with Dana rears as an option starting in '68. __________________ 1965 C30 pickup 350/SM420/4.10's (daily driver) thread 1968 Impala 4 door sedan (future driver project) thread

10-04-2014, 10:11 AM	#9
Budman56 Registered User Join Date: Aug 2011 Location: Patterson California Posts: 1,133	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? what about a different offset in the wheel instead of modifying the rear end? __________________ MY 65 C20 BUILD http://67-72chevytrucks.com/vboard/s...d.php?t=483346 ......................_____ .........________//__{\_____ ,,,,,,,/__(O)___//___/__(O)_/

10-03-2014, 11:17 PM	#4
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? The Eaton HO52 in the C/K20's and C/K30's don't follow the same width differences as the C/K 10's. The Eaton under your truck should be 65.5" wide. There is a member here that put a 2000 14 bolt from a 3500 truck that measured 65.625" wide. Narrowing a full floater differential gets expensive since it is more time consuming than narrowing a semi-floater. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

10-04-2014, 11:27 AM	#10
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? I'm going to look at a 14 bolt out of chevy 2500 after work today. I measured my 62 this morning and face to face was approx. 65" if the axle I'm looking at tonight is within an inch it will work. Wheel offset would probably work but that requires new rims and there not cheap. It also doesn't address the gearing issue. Axle I'm looking at tonight has 3.73's in it. This axle is $300 and cutting and welding in brackets is easy for me. Hopefully it is narrow enough!

10-04-2014, 11:41 PM	#11
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? I forgot to mention that a 14 bolt from a '73-'86 C/K30 or '87-'91 R/V3500 cab and chassis should be narrow enough __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

10-05-2014, 09:39 AM	#13
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? My craigslist contact for the axle got busy yesterday and couldn't meet until Monday now. I'm still excited to find out the measurement. If it's in that 65" ball park I'm good to go. I'm assuming the yokes are different as well, so I'm hoping I can talk him into cutting the driveshaft so I can get that as well.

10-08-2014, 04:40 PM	#14
Flathead Smith Registered User Join Date: Aug 2011 Location: DeArmanville AL Posts: 47	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? One other option which I do not see mentioned is to find a third member from a newer Eaton ¾ (HO52) or 1 ton (HO72) and install it in your rear end. That’s what I did with my 65 C-20, of course it only took me from a 4:56 to a 4:11, but for me that was enough. I did have to cut some out of my drive shaft as the newer style Eaton was just a little longer. Here is how I did it...you will need to scroll to the bottom. http://67-72chevytrucks.com/vboard/s...d.php?t=534896

10-08-2014, 10:41 PM	#15
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? I ended buying an axle out of 1998 4wd c2500. It is the 65.625 so it should work perfect for what I'm doing. It was a 4.11 ratio, wanted to try a 3.73 but I will see how this works and if I need to change it at least I have options. This one was out of a running truck and it only cost me a $100 bucks. Picking it up next Sunday. Once I tear into I will post up some pics of the fun. Matt

10-12-2014, 10:26 PM	#16
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? Question for the axle guru's. This 65.625 axle that supposedly exists is kicking my ass. I picked up my $100 axle out of the 98 4wd c2500. Measured it up once it once it was out and it measures 66.5". Approx 1" to wide. This hub set up looks different than that 99 suburban I looked at last week. Still bought it since I told the guy I would take it even tho it may not work. Any options to take a 1/2" off each side? Different drums or something? Matt Attached Images

10-13-2014, 12:05 AM	#17
Captainfab 60-66 Nut Join Date: Mar 2007 Location: Coeur d'Alene, Idaho Posts: 23,252	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? I do not know of any easy way to shorten a differential 1". The 14 bolt under that other Burb had outboard drums. It is possible that switching the hubs, drums and backing plates could change the width, but I do not know for certain as I have not done that. __________________ Power Steering Box Adapter Plates For Sale HERE Power Brake Booster Adapter Brackets For Sale '63-'66 HERE and '67-'72 HERE and '60-'62 HERE and "60-'62 with clutch HERE Rear Disc Brake Brackets For Sale. Impala SS calipers HERE Camaro Calipers HERE D52 Calipers HERE 6 Lug HERE Hydroboost Mounting Plates HERE

10-13-2014, 12:08 AM	#18
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? Yeah I didn't think so. Probably end up getting a few bucks back in scrap. Oh well. This came out of a 98 C2500. From what I can gather on the internet it is a full floater dually axel. And it didn't come out of a dually.

10-13-2014, 12:14 AM	#19
Ozzy2013 Registered User Join Date: Oct 2013 Location: Elkton Posts: 693	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? Im not sure but seem to remember someone making a disc conversion that made it narrower ans stop so much better.



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10-13-2014, 12:11 AM	#20
66Submarine Registered User Join Date: Sep 2012 Location: Dallas, GA Posts: 1,497	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? As previously mentioned, you might also be able to use a cab and chassis dually axle, since they are narrower; I think something like 63". If you are OK with 4.10's you can also just stick a 4.10 third member in the existing Eaton rear. YMMV, but I recently realized I actually have 4.57's and a tach that reads slow in my C30 I drive everywhere. Have you driven the truck any at this point? __________________ 1965 C30 pickup 350/SM420/4.10's (daily driver) thread 1968 Impala 4 door sedan (future driver project) thread

10-13-2014, 03:37 PM	#22
Mathew21 Registered User Join Date: May 2010 Location: Clinton township, MI Posts: 1,192	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? buckroseau- Here's a post I made about axle widths awhile ago. Read the response #4. http://67-72chevytrucks.com/vboard/s...d.php?t=620030 __________________ It only has original paint once

10-13-2014, 03:59 PM	#23
buckroseau Registered User Join Date: Sep 2014 Location: Buffalo, MN Posts: 92	Re: Narrowing a 68/newer 3/4 ton rear axle, anyone done it? I ended up buying another axle this morning. It was in a running 97 c3500. This time I had the seller pull the wheels so I could measure. It was 65.625 exactly. Paid a little more but at least I have one now. Heading back over to the guys place tomorrow after work with my torch to cut it out. I'll take a few pics tomorrow night and post them up. This axle is not a full floater.

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