67 3/4 ton Corp Axle - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Dave** · 09-22-2002, 08:58 PM

I have a friend that has a '67 3/4 ton with the corp housing and axles underneath the truck. Currently, his housing encases a 10" ring gear, with a 4:56 ratio and is trying to find 3:73's. GM also called this the HO72 housing. Does anyone have the 3:73's? Or know where he can get them? Also, I've checked most manufacturers of gears and this item is no longer in available.
Thanks for your help.

*Fast68Chevy* · 09-22-2002, 11:24 PM

its actually 4.57,
4.56 was i the dana 60;s

and 3.73 was never made for them and i highly doubt anyone makes any either, parts for the old eatons are rare and $$$$

would be better off going and snatching up a '73-up 14 bolt FF with 3.73 in it for 150 or less, even i have one laying around...

if you have coils rear then you'd need coil rear mounting kit form early classic,

14 bolt Ff is a huge upgrade tons stronger and extremely common and more ratios to be found and parts are made and they dont have the flaws that eatons have

eatons were made from 1947 til 72. theres basically no aftermarket following on them at all.

good luck

jostrans68 · 09-22-2002, 11:35 PM

3.9 is the best he can get now I have a new set from Randys I paid 200.00 for make me a offer............ Jack

mikep · 09-22-2002, 11:42 PM

Why not just go with a Dana 60? you can get one with 3.54 gears made for our 3/4 ton trucks all day long for under a hundred bucks and they'll bolt right up. Think the 14 bolt is stronger? HAHAHA . let me take a breathe...OK . HAHAHAHA .

Fred T · 09-22-2002, 11:44 PM

I was told that the 3.73 was available in the blazer, but they are hard to find. You could swap out for a newer 14 bolt and get either a 3.73 or a 3.42. When I priced the 3.73 14 bolt it was around $300.

jostrans68 · 09-23-2002, 01:01 AM

mike If you can get dana 60 coils 3.54 at 100 I will take 5 as every one I have looked at was 500.00 the coil versions are rare............

mikep · 09-23-2002, 07:27 AM

Geeze. I'd sell you the one under mine but I might be using it for a while.

Your'e in Tacoma . Make a run over to Airport auto wrecking between Gorst and Belfair on hiway 3. They have seventeen of our trucks. Most of them fairly complete. They have dozens of danas on the racks too. Thats where I bought a complete dana 60 locker rear for $75 last week. I know for a fact they have a complete dana 60 - 3.54 geared with detroit locker under a 67. Its also got a M28 close ratio 4 speed tranny you could probably get for not much . It is a leaf sprung truck though.

Blazer1970 · 09-23-2002, 07:44 AM

Quote:

Why not just go with a Dana 60? you can get one with 3.54 gears made for our 3/4 ton trucks all day long for under a hundred bucks and they'll bolt right up. Think the 14 bolt is stronger? HAHAHA . let me take a breathe...OK . HAHAHAHA .

A 14 bolt is stronger than a Dana 60, hands down.

mikep · 09-23-2002, 08:55 AM

Tell my dad that. I've had to replace two 14 bolts in his 80 heavy 3/4 ton. He tells me next time he is going with a Dana 60 or a Dana 70. I have never once had to replace a Dana 60 in anything I have owned. That is of course annectdotal evidence but if I look at what top drag racers are using for rear ends in 1000+ hp applications I see Dana 60's and not 14 bolt corporates .The Dana 60 does have a little bit smaller ring and pinion than the 14 bolt but its still massive but the real strength is in the carrier. Compare a posi dana carrier to a posi 14 bolt and you'll see the difference. Plus 40 years of production means parts are readily available as well as complete rear ends with good gears and posi and locker carriers. The last 4 rear ends I have bought were as follows.

4.10 geared detroit locker Dana 60 $75 from the junkyard

4.10 posi dana 60 ... $45 from the newspaper

3.54 geared detroit locker dana 60 with 10 spline axles? Originally from a 440 magnum road runner. I payed $250 for it but it already was the width and bolt pattern I needed for my Camaro.

4.56 geared posi Dana 60 $115 from the junkyard.

I'd take a 35 spline Dana 70 1 ton rear end over a 14 bolt corporate any day of the week .

A girl I work with just bought a new dodge ram with the big cummins diesel. One ton chassis....Dana 60.

Canada20 · 09-23-2002, 04:16 PM

So what kind of cost is there to switching from leafs to coils? I have a feeling that when I'm done my 454 swap next spring I'm going to find the rear on my 3/4 geared way too steep (the engine it has right now is a 292 so I'm assuming the rear is geared for that). I'm pretty sure mine's not Dana which by the way you guys are talking is going to mean some $$$'s if I want to change ratios.

Greg

PS I'm not sure if what I just said is English or not so feel free to ask/demand clarification

**COBALT** · 09-23-2002, 05:38 PM

You can get 3.73s for your corp. axle, but it won't be easy. They were made for the eaton carrier, but only for a very short time, which makes them EXTREMELY hard to find. Give Randy's Ring & Pinion a call (www.ring-pinion.com). Sometimes they get a set in, but rarely, and the shop guys usually sneak them under the counter for their own use. They'll also be used so watch out. Make sure they have a good wear pattern, and that's IF you find some.

Most have been snatched up if they haven't been totally destroyed already. Forget about new. Like someone said the best option for new gear sets is 3.90s. I had them put in to replace my 4.10s. Much better gas mileage, and lower RPM at highway speeds. Unless you wanna go faster than 75 with a 3spd gear reduction then the 3.90s will be ok.

In the long run I think it would be better for you to convert to a new axle like everyone's suggesting. Less cost definitely, because more than likely you'll open that differential up and find out there's a mess in there. It could cost you upwards of $1000 to replace bearings, gear sets, and the type of carrier. With that cost in mind you'd be in better shape to buy an aftermarket Dana 60 with 3.73 off the shelf brand new.

...just something to think about.

Rod · 09-23-2002, 09:15 PM

Have a Dana 60 coil with 3.54 and a dana 60 coil with 4.10 posi sitting here in Manitoba. Make PM offer if someone whats them.

**Dave** · 09-23-2002, 09:48 PM

Thanks for to everyone for all the options. I really appreciate it!I will pass this onfo to my friend and he'll have to make a decision. Again many thanks.
Dave..

UNCLEBOB · 09-23-2002, 11:44 PM

Mikep did you see any dana's for a coil spring rearend 4.10 4.56s for a 68 at airport.

mikep · 09-24-2002, 12:21 AM

I know theres a few coil sprung dana 60's out there under C20's but I didnt check the ratio tags under all of them. Theres a 67 back in the corner that has a locker 3.54 dana 60 but its a leaf sprung rear end and then theres a coil sprung C10 posi but its not a Dana up in the upper section by the school buses and moving vans. Theres a bunch of other dana's under C20's but I think those are the only posi's. He's got a sh!tload of rear ends in the rear end pile. Must be over a hundred. Lots of posi and a few lockers. Remember ... If you have a standard dana 60 you can convert to posi without having to completely set up the rear end. The pinion depth doesnt change and since you arent changing gears all you have to do is set backlash or simply shim the carrier to retain the same distance from a reference point. Either way. Changing a rear end to coil springs from leaf springs isnt all that difficult of a job and 4.10 Dana rear ends are the most plentiful I see and I'm always on the lookout for a good deal on a dana.

Theres a lot of recent arrival C20's in there. Some havent had anything removed from them yet. Most are automatics. Hes got a whole bunch of 67 and 68's for some reason. I'm thinking about heading down and picking up a automatic column just to have one if I ever convert. They want $100 complete and they have some decent steering wheels which is hard to find in 68's.

UNCLEBOB · 09-24-2002, 10:59 AM

I have a ho72 locker 4.57 rearend now in my truck and want to change to a 5 lug setup. I bracket race out at the track alot and would like some decent wheels on the truck. I will try and get out there next monday. Thanks

Canada20 · 09-24-2002, 11:06 AM

So what're the chances of getting a dud rearend from the scrapyard? I'd think that the broken rearends aren't usually what get these trucks taken off the road; more likely engines and transmissions.

Greg

mikep · 09-24-2002, 12:22 PM

When you go to airport wrecking make sure you go to the upper section. I went to that place for a year before I even knew it was up there. Go past the regular truck section up into the path that leads to the woods and you'll find a whole other truck section. Thats where theres a 5 lug 69 C10 with a posi rear end is hiding right next to a mid 60's red and white suburban. That guy has a huge amount of 60's and early seventies trucks in that yard.

Dean · 09-24-2002, 01:51 PM

There is no way a 14 bolt is stronger than the Corp rearend. I have both and there is no comparison. I do agree with parts being a problem sometimes with the Corp. I must have 10 spare Corp rearends just in case, but I've never needed a part. Finding the Detroit Lockers is always a plus. I've been able to purchase new seals and brake shoes. That is all I've ever needed. Just my two cents worth...........

09-22-2002, 08:58 PM	#1
Dave DND Trucks Join Date: Dec 1999 Location: NW Indiana Posts: 2,397	67 3/4 ton Corp Axle I have a friend that has a '67 3/4 ton with the corp housing and axles underneath the truck. Currently, his housing encases a 10" ring gear, with a 4:56 ratio and is trying to find 3:73's. GM also called this the HO72 housing. Does anyone have the 3:73's? Or know where he can get them? Also, I've checked most manufacturers of gears and this item is no longer in available. Thanks for your help.

09-22-2002, 11:35 PM	#3
jostrans68 Jostrans68 Join Date: Mar 2001 Location: Bloomington indiana Posts: 1,182	3.9 is the best he can get now I have a new set from Randys I paid 200.00 for make me a offer............ Jack __________________ [CGTW Member former 67-72 now with a 96 silverado

09-22-2002, 11:42 PM	#4
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Why not just go with a Dana 60? you can get one with 3.54 gears made for our 3/4 ton trucks all day long for under a hundred bucks and they'll bolt right up. Think the 14 bolt is stronger? HAHAHA . let me take a breathe...OK . HAHAHAHA . __________________ No truck :-(

09-22-2002, 11:44 PM	#5
Fred T Cantankerous Geezer Join Date: Aug 2002 Location: Bel Aire, KS Posts: 6,264	I was told that the 3.73 was available in the blazer, but they are hard to find. You could swap out for a newer 14 bolt and get either a 3.73 or a 3.42. When I priced the 3.73 14 bolt it was around $300. __________________ Fred There is no such thing as too much cam...just not enough engine.

09-23-2002, 01:01 AM	#6
jostrans68 Jostrans68 Join Date: Mar 2001 Location: Bloomington indiana Posts: 1,182	mike If you can get dana 60 coils 3.54 at 100 I will take 5 as every one I have looked at was 500.00 the coil versions are rare............ __________________ [CGTW Member former 67-72 now with a 96 silverado

09-22-2002, 11:24 PM	#2
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	its actually 4.57, 4.56 was i the dana 60;s and 3.73 was never made for them and i highly doubt anyone makes any either, parts for the old eatons are rare and $$$$ would be better off going and snatching up a '73-up 14 bolt FF with 3.73 in it for 150 or less, even i have one laying around... if you have coils rear then you'd need coil rear mounting kit form early classic, 14 bolt Ff is a huge upgrade tons stronger and extremely common and more ratios to be found and parts are made and they dont have the flaws that eatons have eatons were made from 1947 til 72. theres basically no aftermarket following on them at all. good luck

09-23-2002, 07:27 AM	#7
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Geeze. I'd sell you the one under mine but I might be using it for a while. Your'e in Tacoma . Make a run over to Airport auto wrecking between Gorst and Belfair on hiway 3. They have seventeen of our trucks. Most of them fairly complete. They have dozens of danas on the racks too. Thats where I bought a complete dana 60 locker rear for $75 last week. I know for a fact they have a complete dana 60 - 3.54 geared with detroit locker under a 67. Its also got a M28 close ratio 4 speed tranny you could probably get for not much . It is a leaf sprung truck though. __________________ No truck :-(

09-23-2002, 08:55 AM	#9
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Tell my dad that. I've had to replace two 14 bolts in his 80 heavy 3/4 ton. He tells me next time he is going with a Dana 60 or a Dana 70. I have never once had to replace a Dana 60 in anything I have owned. That is of course annectdotal evidence but if I look at what top drag racers are using for rear ends in 1000+ hp applications I see Dana 60's and not 14 bolt corporates .The Dana 60 does have a little bit smaller ring and pinion than the 14 bolt but its still massive but the real strength is in the carrier. Compare a posi dana carrier to a posi 14 bolt and you'll see the difference. Plus 40 years of production means parts are readily available as well as complete rear ends with good gears and posi and locker carriers. The last 4 rear ends I have bought were as follows. 4.10 geared detroit locker Dana 60 $75 from the junkyard 4.10 posi dana 60 ... $45 from the newspaper 3.54 geared detroit locker dana 60 with 10 spline axles? Originally from a 440 magnum road runner. I payed $250 for it but it already was the width and bolt pattern I needed for my Camaro. 4.56 geared posi Dana 60 $115 from the junkyard. I'd take a 35 spline Dana 70 1 ton rear end over a 14 bolt corporate any day of the week . A girl I work with just bought a new dodge ram with the big cummins diesel. One ton chassis....Dana 60. __________________ No truck :-( Last edited by mikep; 09-23-2002 at 09:05 AM.

09-23-2002, 04:16 PM	#10
Canada20 Registered User Join Date: Jun 2001 Location: Calgary, Alberta, Canada Posts: 802	So what kind of cost is there to switching from leafs to coils? I have a feeling that when I'm done my 454 swap next spring I'm going to find the rear on my 3/4 geared way too steep (the engine it has right now is a 292 so I'm assuming the rear is geared for that). I'm pretty sure mine's not Dana which by the way you guys are talking is going to mean some $$$'s if I want to change ratios. Greg PS I'm not sure if what I just said is English or not so feel free to ask/demand clarification

09-23-2002, 05:38 PM	#11
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	You can get 3.73s for your corp. axle, but it won't be easy. They were made for the eaton carrier, but only for a very short time, which makes them EXTREMELY hard to find. Give Randy's Ring & Pinion a call (www.ring-pinion.com). Sometimes they get a set in, but rarely, and the shop guys usually sneak them under the counter for their own use. They'll also be used so watch out. Make sure they have a good wear pattern, and that's IF you find some. Most have been snatched up if they haven't been totally destroyed already. Forget about new. Like someone said the best option for new gear sets is 3.90s. I had them put in to replace my 4.10s. Much better gas mileage, and lower RPM at highway speeds. Unless you wanna go faster than 75 with a 3spd gear reduction then the 3.90s will be ok. In the long run I think it would be better for you to convert to a new axle like everyone's suggesting. Less cost definitely, because more than likely you'll open that differential up and find out there's a mess in there. It could cost you upwards of $1000 to replace bearings, gear sets, and the type of carrier. With that cost in mind you'd be in better shape to buy an aftermarket Dana 60 with 3.73 off the shelf brand new. ...just something to think about. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

09-23-2002, 09:15 PM	#12
Rod Join Date: Dec 1999 Location: Eastern - Manitoba Canada, Winnipeg Posts: 4,369	Have a Dana 60 coil with 3.54 and a dana 60 coil with 4.10 posi sitting here in Manitoba. Make PM offer if someone whats them. __________________ Senior active founding member. 70 3/4 ton GMC Suburban 4x4 250/4 spd. 71 1/2 ton Suburban Chevy 4x4, 350/350 72 Chev 1 ton tow truck 402BB w/Holmes 440 wrecker on propane 2005 FLSTSCI Harley Springer 85 FXSB Harley Lowrider 72 Triumph 650 Bonneville 5spd "Poor people don't have hobbies" Quote from wife.

09-23-2002, 09:48 PM	#13
Dave DND Trucks Join Date: Dec 1999 Location: NW Indiana Posts: 2,397	Thanks for to everyone for all the options. I really appreciate it!I will pass this onfo to my friend and he'll have to make a decision. Again many thanks. Dave..

09-23-2002, 11:44 PM	#14
UNCLEBOB Registered User Join Date: May 2000 Location: bremerton wa 98310 Posts: 100	Mikep did you see any dana's for a coil spring rearend 4.10 4.56s for a 68 at airport. __________________ 68 lwb 383 solid roller,250dur, 582lift, afr 210s, 10.8 comp. edel.rpm, 750vs,1 3/4 headers turbo 400, 3500 stall,ford 9 inch 3.89 gears

09-24-2002, 12:21 AM	#15
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	I know theres a few coil sprung dana 60's out there under C20's but I didnt check the ratio tags under all of them. Theres a 67 back in the corner that has a locker 3.54 dana 60 but its a leaf sprung rear end and then theres a coil sprung C10 posi but its not a Dana up in the upper section by the school buses and moving vans. Theres a bunch of other dana's under C20's but I think those are the only posi's. He's got a sh!tload of rear ends in the rear end pile. Must be over a hundred. Lots of posi and a few lockers. Remember ... If you have a standard dana 60 you can convert to posi without having to completely set up the rear end. The pinion depth doesnt change and since you arent changing gears all you have to do is set backlash or simply shim the carrier to retain the same distance from a reference point. Either way. Changing a rear end to coil springs from leaf springs isnt all that difficult of a job and 4.10 Dana rear ends are the most plentiful I see and I'm always on the lookout for a good deal on a dana. Theres a lot of recent arrival C20's in there. Some havent had anything removed from them yet. Most are automatics. Hes got a whole bunch of 67 and 68's for some reason. I'm thinking about heading down and picking up a automatic column just to have one if I ever convert. They want $100 complete and they have some decent steering wheels which is hard to find in 68's. __________________ No truck :-(

09-24-2002, 10:59 AM	#16
UNCLEBOB Registered User Join Date: May 2000 Location: bremerton wa 98310 Posts: 100	I have a ho72 locker 4.57 rearend now in my truck and want to change to a 5 lug setup. I bracket race out at the track alot and would like some decent wheels on the truck. I will try and get out there next monday. Thanks __________________ 68 lwb 383 solid roller,250dur, 582lift, afr 210s, 10.8 comp. edel.rpm, 750vs,1 3/4 headers turbo 400, 3500 stall,ford 9 inch 3.89 gears



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09-24-2002, 11:06 AM	#17
Canada20 Registered User Join Date: Jun 2001 Location: Calgary, Alberta, Canada Posts: 802	So what're the chances of getting a dud rearend from the scrapyard? I'd think that the broken rearends aren't usually what get these trucks taken off the road; more likely engines and transmissions. Greg

09-24-2002, 12:22 PM	#18
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	When you go to airport wrecking make sure you go to the upper section. I went to that place for a year before I even knew it was up there. Go past the regular truck section up into the path that leads to the woods and you'll find a whole other truck section. Thats where theres a 5 lug 69 C10 with a posi rear end is hiding right next to a mid 60's red and white suburban. That guy has a huge amount of 60's and early seventies trucks in that yard. __________________ No truck :-(

09-24-2002, 01:51 PM	#19
Dean Senior Member Join Date: Jan 2000 Location: Cincinnati, Ohio Posts: 1,492	There is no way a 14 bolt is stronger than the Corp rearend. I have both and there is no comparison. I do agree with parts being a problem sometimes with the Corp. I must have 10 spare Corp rearends just in case, but I've never needed a part. Finding the Detroit Lockers is always a plus. I've been able to purchase new seals and brake shoes. That is all I've ever needed. Just my two cents worth...........

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