10bolt front diff tech

[bebe]

Just re read part of your thread...Your axle is more centered then when stock. Is that because the pass side couldnt go any shorter with the H2 halfshaft and D44 diff?

Yes...that's exactly why - which is why I said the TTB Ford might be a better option. Also, the H2 shaft was longer when attached to the stub axle. Remember we had to widen the track width.

And no, the spline count is different front to rear on the stock H3. I posted the AAM Catalog earlier, it's all in there. You will need custom stub shafts - there is no way around it.

 

[bebe]

Curious - did Black Bear ever finish his project and install it?

 

[06 H3]

Not sure. I thought he did. His whole thread was lost on the switchover. I PMed cbetts to see if he had saved that thread. Ill call out to any of the guys who saved threads on the switch over, do you have a thread called something like 8.5in diff w/locker. Even though there's no locker in it he was planning on putting one in hence the thread name

 

[bebe]

Here is my Diff

Notice the Pass side is as short as can be. If you started with a Drivers side drop - you may in theory get it closer, BUT, your stub shaft would be tiny.

Here is what it looks like from the front

 

[06 H3]

would it matter if the shaft is tiny? Tiny as in short, not overall diameter.

I think the best one to start measuring and testing around is 4speed. Hes got the 10 bolt laying around and some POS AAM-7s around. I wish I didnt live so far 4speed. It would be nice if we could meetup and talk about this with the axles in front of us. Either way, I think the first thing that makes me wonder if the actual pumpkin width. The AAM-7 is narrower then the 10 bolt but by how much? That will play a role in where its mounted and how short we can cut the tube.

Where the hell is blackbear? Too bad we dont have his phone # or something. This is like the guessing game with custom007s rig. Pictures help but it would be nice to talk to the builder.

 

[atvspeed4]

By cutting the housing you can make it much shorter than that. Also by internally retaining the axle shafts aka snap rings or c clips like the stock axle you can go even shorter without running a bearing retainer.

 

[bebe]

would it matter if the shaft is tiny? Tiny as in short, not overall diameter.

No - however, the vendor who splined the short side said that it pretty much limited out his machine. It was short enough to the point he couldn't do his signature star spline pattern.

 

[MTUH3]

would it matter if the shaft is tiny? Tiny as in short, not overall diameter.

That's what she said....

Sorry couldn't help it

 

[atvspeed4]

Our vendor that cuts our shafts is having the same problem with our HP 30 build for the s10 diff. The spline cutter can only cut so close to the flange and bearing surface

 

[bebe]

Our vendor that cuts our shafts is having the same problem with our HP 30 build for the s10 diff. The spline cutter can only cut so close to the flange and bearing surface

So I guess it does matter how short the PS Shaft is....well, if you want it splined. Do you use Dean at Performance Cryogenics?

 

[bebe]

I suggest using a 44 - the front Corp 10 bolts were only used from 77-87 in a 28 spline and 88-91 in a 30 spline.

Also - I think getting rid of the C-clip (semi float) gives you more Locking differential choices.

 

[Schwarttzy]

I suggest using a 44 - the front Corp 10 bolts were only used from 77-87 in a 28 spline and 88-91 in a 30 spline.

I'm very sure that this whole thread is because and I'm quoting 4speedfunk on this, "Blackbear just happened to notice that the inboard end (on) his Hummer H3 half-shaft plugged into the 8.5" carrier"




But if the H3 shafts aren't able to slide into the 10 bolt, possibly a very particular 10 bolt, and there is no way to use a completely stock H3 shafts, I'm out and just going to put some band aids on the iron AAM-7 so I can calling it a day.

 

[MTUH3]

Chris, you probably have a good advantage to mess with the stuff. The Rancho kit should give you more room to work with? At least up / down.

I like what Bebe did by going to the 2500 type half shafts (more common part), but could one argue the H3 is more serviceable? I have colorado half shafts at home, and there is a good difference between those and the H3, but if I understand, those particulaly drove the longer control arms.

Does the Rancho kit re-use the OE upper control arm? Would you be opposed to replacing control arms if that mean you got a serviceable, more travel ball joint? Just asking the question.

I have control arm bushings and ball joints coming up for replacement, I have been considering replacing the control arms with something longer (If it could work) / more servicable parts.

Could you get the shaft between joints on the H3 half shaft lengthened? If places like Cardone rebuild the half shafts, there has to be a way to repair broken ones with new joints and longer shafts

 

[atvspeed4]

So I guess it does matter how short the PS Shaft is....well, if you want it splined. Do you use Dean at Performance Cryogenics?

We use Mitchell here in Mass. I should post up a pic of a aam 7.2 8.25 and 9.25 stub shaft. Its pretty impressive how short they are.

I suggest using a 44 - the front Corp 10 bolts were only used from 77-87 in a 28 spline and 88-91 in a 30 spline.

Also - I think getting rid of the C-clip (semi float) gives you more Locking differential choices.

I fully agree that its the strongest option... if it were an option. As I said before, after I actually took the stock diff out and started measuring and test fitting the only way we will fit a larger diff is running stock CVs or running 1500 CVs with a really really short stub shaft aka the flange just clearing the mounting bolts of the diff mount. We just do not have enough clearance under there.

Chris, you probably have a good advantage to mess with the stuff. The Rancho kit should give you more room to work with? At least up / down.

I like what Bebe did by going to the 2500 type half shafts (more common part), but could one argue the H3 is more serviceable? I have colorado half shafts at home, and there is a good difference between those and the H3, but if I understand, those particulaly drove the longer control arms.

Does the Rancho kit re-use the OE upper control arm? Would you be opposed to replacing control arms if that mean you got a serviceable, more travel ball joint? Just asking the question.

I have control arm bushings and ball joints coming up for replacement, I have been considering replacing the control arms with something longer (If it could work) / more servicable parts.

Could you get the shaft between joints on the H3 half shaft lengthened? If places like Cardone rebuild the half shafts, there has to be a way to repair broken ones with new joints and longer shafts

Any shop that can respline shafts can make you a custom shaft for your cvs. Its nothing special I already asked if they could. We just really wanted to use off the shelf parts when we started this idea.

 

[MTUH3]

I agree that stock parts are the way to go. My thinking is that if you need need to repair / replace bushings and ball joints eventually, and to repair / replace the upper ball joint you need to buy a whole new upper control arm. That might be the time to upgrade. Bolt in ball joints are more field serviceable than the press in stuff

 

[06 H3]

Carl, the H3 rancho kit uses oem uca mounting points and uses drop brackets for the LCA mounting. I have plenty of room. This project will only happen if its mainly bolt in with some minor modification. If not then **** it. It would just be easier to do a whole custom subframe and build everything from scratch like bebe did. Even if I had to use some bizarre ford half shaft idc. As long as I don't need custom one off half shafts or one that offers less travel then the H2/H3 one does I'm fine

 

[bebe]

We use Mitchell here in Mass. I should post up a pic of a aam 7.2 8.25 and 9.25 stub shaft. Its pretty impressive how short they are.



I fully agree that its the strongest option... if it were an option. As I said before, after I actually took the stock diff out and started measuring and test fitting the only way we will fit a larger diff is running stock CVs or running 1500 CVs with a really really short stub shaft aka the flange just clearing the mounting bolts of the diff mount. We just do not have enough clearance under there.



Any shop that can respline shafts can make you a custom shaft for your cvs. Its nothing special I already asked if they could. We just really wanted to use off the shelf parts when we started this idea.

Yep - we went through the same process, pulled out the oem set up and stared at it LOL 6 months fiddling - 3 months building.

Custom length shafts are easy to have done....it's the stub shaft with a flange that we are talking about here that gets tricky when it's too short because of the splining machine.

BTW it's good to see you came up with the same conclusion regarding fitment of a larger diff. (There are only so many ways to skin this cat). We chose to go wider because I wanted to use off the shelf parts. Just about everything I did was off the shelf stuff, axles, bearings heims, bushings, knuckles, wheel bearings and steering rack etc.We just configured it differently.

The diff and mounting are custom...but they don't break.
The A-arms are custom - they don't break

Just about everything I can get at NAPA

Dang, I can't believe it's been 2 years already.....huh. KOH in Feb will be 2 years the Bebemonster has been on the road and the trail.

 

[4speedfunk]

There's a bunch of suggestions flyin around on several different designs but, long story short...the 8.5 10-bolt is the only axle that can be swapped in place of the stock AAM-7 without any other mods. I think that's the key to making it work. Custom half-shafts, flanged axles, moving the diff around, using full-size half shafts, etc....sort of defeats the purpose. I mean...if you're gonna do all that, you should shave the frame rails and start from scratch, Bebe style.

I'm focusing on a true cheapo fix. Blackbear's 10-bolt is a true junkyard build. We're talkin less than $400 for the finished product! The best part about it, is that 100% of the fab can done ahead of time...because the axle housing is 100% of the swap. There are no other items to mod, change, track-down, or fabricate. You get the axle done ahead of time...and you can swap it in 2 hours with zero down time. I think that would appeal to lots of weekend mechanics, that don't have the funds or the time for anything more custom.

I'll be messing with my junk pile over the weekend...let you know what I find out.

 

[atvspeed4]

If you have a spare stock diff you are right it could be built ahead of time. Heck if I did not have to pull the diff out of my daily driver everytime I would have already built this. Around me a front corporate 10 bolt is $100 already pulled, I already bought the special welding wire ugh $190 for 11lbs and I have a machine shop I already work with

 

[06 H3]

Thanks 4speed! That's what I'm looking for

 

[bebe]

Axle plunge: What is it? I saw Mel wade talked about it the other day when working on a long travel 4WD system for a GMC 2500 and asked him what axle plunge was but never got a response? Less plunge is better or is more plunge better? (googled it without much luck)

Plunge is a very elusive animal - I had to pick brains for weeks until I got the straight poop from Jess at Highangle.

All CV's move much the same way, however inner CV's, mostly the tri-pot/pod type also move in and out of the joint.

This allows the axle to get longer as it travels through it's arc up and down. As the axle travels up and down the inner end pulls slightly towards the outer side of the cup it's held in. This keeps the axle from binding and breaking the cup.

So in essence the axle plunges in and out of the Tripot cup as it move up and down.

To set axle plunge means to set where distance wise the axle begins at center. If you set it too far in the cup. it will bind at full up or down travel. If you set it too far out, it can exit the cup entirely and break it as it goes in. The best setting is at center, and it's hard to do unless like we learned you take the boot off and chuck all the grease so you can see exactly how you are setting the track width and watch it as you cycle the suspension.

 

[bebe]

There's a bunch of suggestions flyin around on several different designs but, long story short...the 8.5 10-bolt is the only axle that can be swapped in place of the stock AAM-7 without any other mods. I think that's the key to making it work. Custom half-shafts, flanged axles, moving the diff around, using full-size half shafts, etc....sort of defeats the purpose. I mean...if you're gonna do all that, you should shave the frame rails and start from scratch, Bebe style.

I'm focusing on a true cheapo fix. Blackbear's 10-bolt is a true junkyard build. We're talkin less than $400 for the finished product! The best part about it, is that 100% of the fab can done ahead of time...because the axle housing is 100% of the swap. There are no other items to mod, change, track-down, or fabricate. You get the axle done ahead of time...and you can swap it in 2 hours with zero down time. I think that would appeal to lots of weekend mechanics, that don't have the funds or the time for anything more custom.

I'll be messing with my junk pile over the weekend...let you know what I find out.

Get it on you!

 

[4speedfunk]

Okay yall. I've been out in my shop all day today (Saturday), and I got to the bottom of the GM 8.5" 10-bolt IFS. Long story short...this is completely do-able! Cudos to Blackbear wherever he is. Its so simple I feel a tad stupid for not looking at it sooner. I've got one on the bench...tore down to the bare housing. It does in fact share the same exact splines as the AAM-7. The stock Hummer stub-axle and half-shafts plug right into the 10-bolt carrier, just as rumored. The more I sit and stare at it, the less intimidating it is. I also have an AAM-7 torn apart, to see just how the coupler dohinky works. That looks to be no problem either. At this point, I got it all figured out in my head....just gotta start choppin. This housing has a date with the industrial band-saw Monday. I seriously think I could knock this out in 3 or 4 hours of machining time. It also looks like I might be able to grab one of the stock 10-bolt shafts and chop it, re-spline it, and use it for the new stub axle.

This could be the Rosetta Stone for H3 front axles! Upgrade to a larger 8.5" ring gear...a cast-iron, one-piece housing...the gear ratio of your choice...a locker of your choice...all without welding or fabbing anything. The strength of the GM 8.5" remains debatable but, since its the only axle that allows the use of stock half-shafts....I consider that a dead issue. Whatever it's true strength is...its way better than the stock axle. I'll take a bunch of pics and post the process on a separate BUILD thread.

I have a solid axle in my H3, so I have no way to test this. I'm probably gonna need a volunteer. Any takers?

 

[mkmcgreg]

If I understood what you were doing I'd consider all I got from that was something about a doohickey... Your more than welcome to reference mine but I am timid to commit to something I have no idea what it is lol

 

[06 H3]

I will!