# 3/4 ton front axle



## home rescue (Oct 25, 2003)

I have found a set of 3/4 ton axles and want to swap them with my axles. I now have full time for wheel drive in my old gmc, and I want to keep the fulltime hubs, but the 3/4 ton front axle is lock in lock out hub. Question is did gm make fulltime hubs on 3/4 ton axles bask in the 70s or 80 s and if they did can I just buy full time hubs to swap out with the lock in lock out hubs. Hope I asked that right. Merry Christmas everyone.


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## tuna (Nov 2, 2002)

They did make 3/4 ton full time but it would be a waste of money,just leave yours locked.


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## PackRat (Dec 14, 2004)

I've converted full time hubs to part time, so I don't see why the proccess couldn't be reversed. I think the only really important item, is that snap ring on the end of the axle shaft, to keep the lock ring, from working back and forth. Might take a couple tubes of silicone to get the full time caps to seal again.

The bad news is, that your front axle is the same as the 3/4t axle, from the ball joints in. No heavier, just bigger hubs.

If you're trying to upgrade, you need 1-ton axles, so you can have the Dana60 front, and Dana 70, or Corporate rear.


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## derekbroerse (Mar 6, 2004)

I take it that this is a Corporate 10 bolt (1978 or so and up), and not a Dana 44 (pre-1978 or so)? What year axles are they (original vs. replacement). I don't know if the hubs are the same from the one axle to the other, they may well be.

I have a fulltime 4x4 equipped K5 with the Dana 44. Seems to come apart pretty much the same way as the lock-outs. I agree with the above opinion though, that it isn't worth the changeover unless you can reuse your old parts. Just leave them locked if thats what you want, but for fuel mileage's sake you can release them (for long trips etc.)

As stated above, the Corporate 10 bolt front is the same axle from 1/2 to 3/4 ton trucks, with different hubs (6 lug vs. 8).


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## home rescue (Oct 25, 2003)

thanks , I wiil try to determine what axles they are, the truck I am trying to work on is a 79 gmc with fulltime hubs, tough old truck don't want to retire it, it's a real workhorse, but it's only a 1/2 ton, 4 leafs front and 8 leafs in the back. Hope I don't have the corporates have not heard good things about them.


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## derekbroerse (Mar 6, 2004)

It's probably the same as my '79 GMC half-ton. Probably the ten-bolt corporate front, and twelve bolt rear. Newer 1/2 tons got the ten bolt rear as well.

The 3/4 ton axles will likely be identical on the front, and a 14 bolt rear (of which there are two types--full and semi floater)

What is your goal with the truck? Why are you considering the change? What do you use the truck for?

For most purposes (other than offroading and giant tires) the half-ton stuff is fine. Whatever you end up doing you need to make sure the gears front and rear match or you will break something.

The 14 Bolt full floater is a very beefy axle and is a favorite of the rock-crawlers etc. The only GM axle that is larger for pickups is the Dana 70HD in the duallys. It has a 10.5" diameter ring gear. The 14 bolt semi-floater is also fairly beefy (9.5" ring gear) but has the axle shafts held in with c-clips like a car or half ton axle.

What everyone needs to remember is that any part can break thru use and abuse. The front axle of choice is the Dana 60, like my 4x4 dually has. Most think it is bulletproof, but its not. Even just pushing heavy snow, I sheared off my left axle shaft last year.

Corporate 10 bolt axles work very well if they are used in the right application.
For comparison, they have an 8.5" ring gear. The 12 bolt has an 8.875" ring gear, and the Dana 60 has a 9.75" I think...

Think of it this way, its lasted this long, right?


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## home rescue (Oct 25, 2003)

what I am doing is pulling a 7,000 lb dump. Also when i am plowing 7 1/2 meyer blade with extra steel in mold board and a t-1 scape bar, which makes it alittle heavier than a stock blade,tailgate spreader and 1500 to 2000 lbs of treated salt and toolboxes, so basically just wanted to beef it up alittle more, already have heavier springs. I do know there are limitations and my 1/2 ton will never be a 1 ton, but my old gmc is a tough truck still yet and does one heck of a job for me, very seldom lets me down. I quess I'm just to attached to the truck to buy a new one plus would hate to rough up a new one, and when I do get a new one but I will probably not get rid of the old girl. Believe it or not 2 winters ago it pushed 2 foot of snow off of my lots, because I was out of town on the weekend when that big snow hit. A your right its done a good job this long so I probably won't mess with it after hearing some of these comments and information, with 3 years with aplow no bearing problems in the axle itself, just one bearing in the fulltime hub, a ball joint and one tie rod end.


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## PackRat (Dec 14, 2004)

Your 1/2 has the same frame as a 1ton. Like I said, if you find 1-ton axles, you will make a good upgrade. The 1/2's used longer leaves on the rear, for better ride.
I've never been a fan of full time NP203's. The chain runs all the time, and is known to stretch, which means $$ for chain savers, or new chain and sprockets.

Just for arguments sake. My 70 K10 plowed a lot of snow, with a Dana 44 front. I put 3 rear leafs under the flat main, and lifted the front 2-3". Added some leaves to the rear, too. I was using it for a wrecker at the race track, and never broke.


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## derekbroerse (Mar 6, 2004)

One ton frames are definately NOT the same as a half-ton. They are heavier steel and the 'c-channel' is several inches taller.

You will find that unless someone doesn't know what they have, one-ton axles will be worth as much as the rest of your truck's value.

If most of the weight is on the rear, check the 3/4 ton axles out as the 14 bolt FF is the same as the one-ton.... and very readily available and cheap. It's the Dana 60 that is rare and expensive.


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## gearhead (Nov 30, 2004)

derekbroerse said:


> I take it that this is a Corporate 10 bolt (1978 or so and up), and not a Dana 44 (pre-1978 or so)? What year axles are they (original vs. replacement). I don't know if the hubs are the same from the one axle to the other, they may well be.
> 
> I have a fulltime 4x4 equipped K5 with the Dana 44. Seems to come apart pretty much the same way as the lock-outs. I agree with the above opinion though, that it isn't worth the changeover unless you can reuse your old parts. Just leave them locked if thats what you want, but for fuel mileage's sake you can release them (for long trips etc.)
> 
> As stated above, the Corporate 10 bolt front is the same axle from 1/2 to 3/4 ton trucks, with different hubs (6 lug vs. 8).


You will have to leave them locked in all the time, I had a full time truck and when you unlock the front end with a fulltime transfer case the truck will not move unless you put a part time kit in the transfer case


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## derekbroerse (Mar 6, 2004)

Interesting.... but I suppose it makes sense, as it would be spinning thru the spiders in the internal differential in the transfer case.

OK then, that being the case, there is an NP203 and front Warn lock-outs in my '79 half ton, which I 'eventually' am putting on the road for a second plow truck. I have never operated the 4wd b/c the front driveshaft is missing...

So you are telling me it has a part-time conversion kit in it? What would the shift pattern actually be then?


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