10bolt front diff tech

[06 H3]

Starting this thread up...After I repair and install squeakys new to me 4:1 transfer case it would be time to tackle the front end. Some may disagree with me as I am "polishing a turd" but I think this will suite me the best. If it all fails and sucks then I can look into a low buck SA deal.

So my thoughts and concerns are these:

First off, I know this is not a big D60 that can handle extreme abuse but I think this can handle the 37-38s with ease. The ring gear is about an inch bigger but will this require any modifications to the rear end of the rancho crossmember? I would prefer to not make any modifications to it. Lets say this axle does fail and I am away from home I want to be able to throw a stocker back in.

Can we put a different yoke in the back of the diff so we can use the same H3 driveshaft (stock or 4speeds double cardan shaft.)

Will the use of colorado mounts get rid of the need for a rear bushing?

Seeing this is still a 3 piece design will a truss like http://www.hummer4x4offroad.com/forum/showthread.php?3333-Front-axle-beef-up this help?

Will the #2 axle shaft in the diagram have to be custom or can it be reused seeing they have the same spline count and length would be the same? I have heard of these failing. Can be cryo treated or custom made with chromoly...

I also plan on doing an E locker or ARB locker and RCVs, I wonder why the RCVs only are the outer end not the inner part of the shaft.

http://www.rcvperformance.com/product-details.aspx?sku=CVJ3906

Ill think of more but I wanna start getting the ball rolling on theories, problems and usability. While I am at it I wanna max out on flex. I did some measurements and found this interesting, our CVs when measured like this

Are netting near similar travel of this H2 shaft. Now we gotta use it. I gotta remeasure and double check but I think this can be a viable solution!

Post up questions thoughts concerns and whatever else.

 

[4speedfunk]

I got tons of info on this...and also photos of the machining process that Blackbear did. I tend to agree about polishing the turd...but this turd stinks much less than the AAM-7! I also got two of these axles laying in a pile to experiment with.

Your concerns...my responses:

-D60?...jeez. Way too much axle for a daily driver. They are MASSIVE and it is very tight under there.
-Handle 37"s & 38"s with ease?... Uh, I'm not so sure about that. It will handle them...but you're well into the red zone with 37"s.
-Trail replacement with a stocker?... Forget that. You'll be running different gears anyway.
-Driveshaft?... Use the stock 10-bolt yoke,(same U-joint). A stock shaft might work, or convert to a Cardan jointed one.
-Colorado mount's?... I'de go custom, especially if you got a Rancho lift. I got pics of Blackbear's snout...he welded on an ear similar to the AAM-7's.
-Truss?... Nah. Its not a three piece design. It will be plenty stiff...least of your worries.
-Stub shaft?... I don't know if you can use a stock H3 stub shaft. It might be too long. I got one laying around. (BTW...thats a Colorado AAM-7 diagram and the stub shaft is different.)
-RCV?... I gave up on that company. Repeatedly ignored emails and phone calls. Stock half-shafts are plenty robust, IMO. The only downside is the limited angle.
-Bolt-in Full-size half-shafts?... Nah. If you're going that direction...use a D44, and do it like Bebe did. The whole point of using the 10-bolt is that it shares the same splines as the AAM-7, and the stock half-shafts plug into it. Also you can bypass all the custom work (including custom flanged stub axles).

These axles are considered to be the wimpy replacement for the D44, and they share many of the same outboard parts. Thats why I have a pile of em (I rob the hubs and knuckles off them). I know several guys that run these in full-size trucks and Blazers. They hold up okay but, they are sort of laughed at among off-roaders. You can get any number of lockers and gearsets. All of the ones I get are 2.73 or 3.08 gears...an obvious attempt to get better MPGs from these 70s-80s era trucks. I think if you keep the stock half-shafts and suspension travel, this would be a big improvement. If you're after more IFS travel...you need to go the Bebe route. If you are after mad flex...go solid axle.

 

[Portager]

Finish what you started before starting something new. :emb:

 

[06 H3]

This is the planning phase I'm not making a purchase or junkyard run until I'm done

 

[06 H3]

you think 37s will be the same as running 35s on the stock diff?

I wanna keep the bolt in OEM axle as an option in case do I have issues with this one and want to switch back. I dont want some chopped up rancho crossmember that will never allow me to run the OEM one again.

Stub shaft will need to custom then? Shouldnt it work I thought they would have to be the same length.

As for the stock shafts, I mean to keep em or the RCV stock shaft. Im just saying that I think we are using way less travel then we can. Samco fab claims you can pull 8inches of travel out of the H3 front end...They said that on racedezert.

I wonder whats cheaper. Buying and shipping one from you or heading down to the yard? Are yours already chopped up?

Can you post more pics of this axle?

 

[4speedfunk]

Okay. I'll go on record saying this..."Having the option to re-gear far superceeds any other reason to do a diff swap". Of course this only applies to running 35" and larger tires. Sure, extra strength is also a good reason but, the 5-cly. really needs help with big tires. The only way to get that help is with a re-gear. I think an H3 with 4.56s and 37"s would be almost un-drivable (with any diff). So IMO...a re-gear is a must. My H3 loves 5.13s with 35"s or 37"s...I'll never go back. Milage is awful...but it was awful before, so I don't care. I can cruise 65mph at 2000rpm all day...13mpg.

The only way to keep your Rancho kit un-modified is to build the new housing with identical attachment points. That might tough do to given the size difference. The stock mounting system blows and I would advise changing it anyway, even with a stock front housing.

Jury is out on the stub-shaft. Because of the larger physical size...you might have to scoot the pumpkin to the driver-side a tad. That means that the stub shaft may be too long. I think the only critical dimension to maintain is the over-all length. It needs to be identical to the AAM-7 so you can re-use the stock mounts on the frame and also the stock half-shafts. Mosier axle is in my backyard and they can make one if you need it. Fortunately...its a VERY simple part...no flanges, tapers, or seals to deal with. Its just a simple floating shaft...should be cheap to make. I can also chop a stock one down if the splined area on each end is long enough.

I wouldn't attempt 8" of travel without some real ball-joints and CV shafts. Unlike a traditional solid axle rig...the H3's IFS doesn't need travel. That's why GM only gave it 4". It does great with only 4" as long as the TC sytem is working. The computer is the "big equalizer".

I have absolutely ZERO invested in my 10-bolt pile. In fact...until yesterday, they were heading to the recycler! But now you got me thinkin. I have access to some crazy good machinists that occasionally get bored, and they love a good challenge. I'm gonna grab an empty 10-bolt housing...one of my AAM-7s...Blackbear's photos...and pay a visit to my guy. We'll have a jamb-session, and I'll let you know what it might cost. Since you're out there in California...I have no doubts it would be cheaper to do the chop here and ship you one. I swear I don't know how you guys pay what you do for stuff out there.

 

[MTUH3]

I am listening. I want to rear gear, bad.

Come January I might have the opportunity to rub elbows with some guys from RPG. They build up longer travel control arms with upgraded ball joints. I will see what they think it takes to build up a set of custom control arms. Or Bebe can ship us hers.....
I am debating on pulling the control arms this spring to replace bushings and ball joints. That would be the time to do something different.

 

[06 H3]

Great 4speed! Its good to see Carl jumping in here as well. It sounds like we may slowly make better and better front ends for these things...

Yea we get raped in CA. Let me know what I can help with...lol I like tinkering with stuff.

 

[alrock]

I think MaxPF was running the 10 bolt under his K5 Blazer just as suggested earlier. He may be able to offer some insight

 

[06 H3]

Great idea Alex! He has tons of info about everything lol...let's get him in here

 

[mudbug]

I am in again if some one can figure it out.

 

[bebe]

Before my brain explodes - what size 10 bolt?

Keep in mind I've already done this.....Max may be better a processing all this....information.

 

[06 H3]

8.5?

 

[bebe]

So you're saying this is an IFS AAM 8.5" Front Axle?

Out of what?

There is no such animal in the AMM Catalog.

http://www.aam.com/resources/pdf/file-20100121124211.pdf

The 2 larger size AAM are clamshell style. (AAM 825 and AAM825)

 

[06 H3]

I think it's the corporate 10 bolt front axle under older blazers then Blackbear chopped it up. Same spline count as our aam stock axle

 

[bebe]

Ok - this WAS a (rear) straight Axle that Black Bear tried to do like we did, but keep the stock H3 axles and the stock stubs shafts?

 

[bebe]

 

[06 H3]

this thread was started because of this thread.

http://www.hummer4x4offroad.com/for...5-Differential-end-brackets&p=76061#post76061

ATV...your parts are coming via USPS, look for them on Friday or Saturday. Thanks.

Guys...you need to check out an IFS front axle build from a guy named "Blackbear". He used to be big cheese over at CHO before the Hummer-gate affair. Anyway...he took a 10-bolt front axle from a 70's Blazer and modded it to accept stock H3 half-shafts. The big advantage of using this axle is that it shares the same axle splines as the AAM-7...so you don't need to go full-custom with the build. You can leave the rest of the front-end alone, and simply replace the middle part. This axle is very common, and although its not the strongest thing out there...I'm sure its a step up from the stock unit. You can get gears & lockers for them too. Here's a teaser pic of the completed 10-bolt with the passenger-side half-shaft installed. The drivers-side simply re-used the stock half-shaft receiver....

View attachment 7882

I never found out if he finished this...but, it was looking really good when I got these photos. I have more pics if interested.

P.S. I have a pile of these 8.5 10-bolts, if anybody wants one.

I wanted to go back to the build thread Blackbear originally did but that thread is long gone. Maybe one of the tech guys saved all the threads when we did the switch over. I would love to see that thread again....

The main reason this axle setup appeals to me is that it keeps the stock shafts and keeps the stock stub shaft (or does it?) 4speed said here that it may not

The only way to keep your Rancho kit un-modified is to build the new housing with identical attachment points. That might tough do to given the size difference. The stock mounting system blows and I would advise changing it anyway, even with a stock front housing.

Jury is out on the stub-shaft. Because of the larger physical size...you might have to scoot the pumpkin to the driver-side a tad. That means that the stub shaft may be too long. I think the only critical dimension to maintain is the over-all length. It needs to be identical to the AAM-7 so you can re-use the stock mounts on the frame and also the stock half-shafts. Mosier axle is in my backyard and they can make one if you need it. Fortunately...its a VERY simple part...no flanges, tapers, or seals to deal with. Its just a simple floating shaft...should be cheap to make. I can also chop a stock one down if the splined area on each end is long enough.

So who knows but I think this can be done with some time and effort. First thing we need to do is all get in here and decide if this axle was a front or rear. Some say front some say its a rear...Once we get that figured out so we dont go to a junkyard and buy the wrong axle we can move onto the stub shaft deal.

 

[atvspeed4]

I believe the housing is the same front or rear. Obviously the tubes are different and the carrier may be different but both of those would be replaced anyways. So you can start with a front or rear since its a low pinion.

Sent from my PC36100 using Tapatalk 2

 

[4speedfunk]

Blackbear's axle was a front. I have pictures of it sitting in an over-grown field before he did anything to it. These came in GM 1/2-ton trucks and Blazers...all the way from the mid 70s up to 91. Its the standard light-duty solid front axle that came in all of these trucks. Dana 44's came in both 1/2t and 3/4t versions but I believe the 10-bolt only came in 1/2tons....I've never seen an 8-lug front 10-bolt. It has an 8.5" ring gear and I'm fairly certain its identical to all the other millions of rear 8.5"s that came in Novas, Camaros, Chevelles, Impalas, 2WD trucks...pretty much forever. Ultimately...this axle evolved into the 8.6" that is in the rear of the H3. I often wondered if you could start with an Adv. Pak REAR axle, and do the same mods to run it in the front position. That would be great because its already got matching 4.56s and an electric locker already installed! I don't know what this would do to the wear pattern, or if this is a good idea. I've never known anybody to do it. For our purposes, I don't think it matters if you start with a front or a rear casting. The front is a probably a better choice because its designed to be ran in that position, and also because it has the typical "cast-in leaf-spring perch" which gives you more material to work with when machining the CV-shaft bearing & seal. So...I think starting with a front is a better idea.

I run across these turds all the time because people mistake them for Dana 44s. The exterior dimensions are the same as a D44, and they share all the same outboard parts (knuckles, hubs, rotors, blah blah). Whats different is the center casting and the differential inside it. They share the same outer shafts (19 spline) but the inner shafts are different (28 vs. 30 I think). In a bizarre twist...Blackbear just happened to notice that the inboard end his Hummer H3 half-shaft plugged into the 8.5" carrier. Bingo! I think thats when the light bulb came on. That means that the AAM-7 and the GM 8.5 share the same shaft size and spline count. This discovery means that there is a possible replacement for JUST THE AXLE...rather than trying to somehow mate H3 half shafts to some other differential. If you can figure out how to seal the plug-in type half-shafts...you can avoid any weird half-breed CV shafts, adapters, or expensive custom stub axles. In essence...its a bolt-in replacement. Of course the story is more complicated than that...but, thats the summary of why the lowly 10-bolt is a good candidate.

I have more questions than answers at this point, and I have thrown many of these axles away after robbing the hubs & spindles off them. I've always considered them nothing more than donors for the Dana 44 outboard parts. I got two of em now, and also a couple AAM-7s lying around. So, I'm looking deeper into this project. Actually...it looks to be a fairly simple process. I have two major concerns and both of them are wide open for debate:

1. Strength and perceived reputation of the GM 8.5 10-bolt.
2. Welding cast iron. (It will require some welding)

 

[MTUH3]

Great discussion folks. I feel 0.005% smarter already. Most of this stuff is still a little over my head

 

[Schwarttzy]

I welded bunch of metal to my 8.8 housing, had some potential hang-ups that we took care of, and I had no problems. I have also read the only thing your really have to do to weld cast Iron properly is bake it in an oven to 500 degrees.

By the way I'm very interested in this over a SA and plan on figuring this out sooner or later too.

 

[atvspeed4]

Its not cast iron, its cast steel and because of that it makes it a little easier to weld to if you have the right wire.

 

[06 H3]

CJ this is from the other thread...certain types of wire can do it.

#2 We contacted and worked with a company that produces welding wire to get hold of a wire that could weld to the housing without requiring pre/ post heat or peening. No it is not just a high nickle rod such as you see people posting like a 7018!!! With this wire we were able to weld to the dana 30 IFS we are working on for the S10 vehicles. The shop doing our welding did several test samples under many tons of pressure and are very confident in this application. What is most important with welding a third mount to the pinion is that the material is very thin here and you need to make sure it is properly reinforced and you do not damage the pinion bearing

On the perceived strength issue it's up in the air. From a pure size aspect this ring gear is an inch bigger, throw 5.13s in there is your pinion as weak or weaker then the current aam 7.6 with 4.56s? Who knows. Even our rear 10 bolts are viewed as turds in the offroad world and I see many posts on other sites advising people to avoid 35s but bebe runs 38s without issue. I have a spare rear axle shaft but its not a concern enough that I carry it wheeling. Back to the front and perception. It should be stronger, it's more stout. I've read that some run 37-39s with big block V8s without issue and others snap them on 32s. Who knows but I think anything is an upgrade to the current setup. If we can figure this out it may be a stepping stone to modifying other housings and tubes to work. More one off parts but it could work.

When you did the solid axle what was the biggest gain offroading for you? The added flex or the regear helping more on the trials?

Can you post up some more pics of this setup

 

[bebe]

this thread was started because of this thread.

http://www.hummer4x4offroad.com/for...5-Differential-end-brackets&p=76061#post76061



I wanted to go back to the build thread Blackbear originally did but that thread is long gone. Maybe one of the tech guys saved all the threads when we did the switch over. I would love to see that thread again....

The main reason this axle setup appeals to me is that it keeps the stock shafts and keeps the stock stub shaft (or does it?) 4speed said here that it may not



So who knows but I think this can be done with some time and effort. First thing we need to do is all get in here and decide if this axle was a front or rear. Some say front some say its a rear...Once we get that figured out so we dont go to a junkyard and buy the wrong axle we can move onto the stub shaft deal.

What about 4diggers stuff - he did it before me