10bolt front diff tech

[4speedfunk]

Thanks for the tip on the welding.

Those rumors about the 10-bolt is why I called it "perceived" strength. I don't have any actual experience with them to form an accurate opinion. But around here, they're considered weak. I think the Dana 44 or the 10-bolt is a HUGE step forward from the AAM, as long as you want to fart around with getting it installed. ANY SAS is not cheap or simple. A D44 IFS is not cheap or simple. Beefing up the AAM might be cheap but, does nothing to help with the gearing. So the 10-bolt IFS has the makings (at least initially) of a good, cheap, available, upgrade. Even if its not bullet-proof, its at least 50% stronger than stock AND YOU CAN RE-GEAR. So, IMO its worth looking long & hard at it.

My SAS is not "crazy flexy". I'm not interested in an RTI ramp test or serious rock climbing. I just want my H3 to be more durable. Its very mild-mannered and rides, steers, and brakes (not breaks) nicely. It also tows very well. That was my intent from the start, and sometimes I regret not going a tad more wild with it. But staying true to what the H3 is all about...its still a great ride on the highway, while at the same time it flat-out destroys the local trails. I don't wheel it hard and quite frankly...I don't have to. I can idle right up and over stuff that used to take me 5 or 6 running attempts, so it does what I wanted it to. It will go places that I don't have the balls to take it...so, I feel I've reached the plateau on this build. The 37"s are awesome on the trails but, they do rob some practicality on the street. The re-gear doesn't really improve off-roading...it improves on-roading. It puts the motor back into the optimum RPM range on the highway.

I got future plans for another SA H3. I hope to make it lower, lighter-weight, and more suited to hard-core stuff. I'll be using aluminum THORparts bumpers, and I'll gut a bunch of the factory mall-options, (seriously...does anybody use that rear wiper?). I plan to cut the top off it and build it cheaper...probably from a salvage, so I might be a little more prone to flog it.

 

[4speedfunk]

4digger's was the ultimate low-buck IFS build. I had a chance to buy his D44 IFS for $1200 but passed. It worked I guess but, I never liked the mounting system he came up with. It used a piece of threaded rod bent around the snout to secure it against a custom crossmember. He swore it was stout...but I couldn't get past that. It used a Ford HP D44 IFS casting (moved over to the passenger-side), custom half-shaft on the passenger-side, and a stock H3 half-shaft on the drivers-side. It also used a custom stub shaft. Too much custom stuff for me. That's the real turn-on about Blackbear's 10-bolt design...all stock parts. It makes maintaining and repairing a snap.

 

[06 H3]

Yep, bebe that's why I didn't go 4digrs route. I want more readily accessible parts. I give him props for that and I don't think Blackbears required a custom crossmember. Another plus to me... If Blackbears deal never come up I'd go 4digrs route but the less custom the better for me.

 

[atvspeed4]

Im pretty sure the dana 44 IFS is High pinion so I am not sure how the heck they 4digr was able to make it fit. We couldnt even make a HP 30 fit.

 

[06 H3]

The new crossmember he made probably hung much lower

 

[atvspeed4]

But the centerline of the height the cv where it goes into the diff must be the same or real close to stock. Even with the HP 30 when we actually fit it up there and lowered the diff 3/4" the pinion was too high and the skidplate hit. Hmmm if I remember right he had to cut the skidplate so maybe that's how it fit

 

[bebe]

I hope this helps as a perspective:

Any diff you use that has a larger ring gear will equally displace the axles. It's wider than the AAM 760 which the track width and ALL the mounting points, pivot points, Ackerman/King Pin Inclination was built around. 'Tis the CENTER OF THE UNIVERSE for the front end of the H3.

The D44 is wider, the chopped 10 bolt axle in the photo above is wider. For what it's worth, I reject the idea that the H3 AAM860 Rear axle is "weak" per se - I've not had any issues with it other than the E-locker pins. Add to that that the D44 is an 8.5" RG and the AAM860 is an 8.6" RG....well you get where I'm going here.....they are the same!

How a D44 can be stronger than an AAM860 is silliness. But then again - my rant includes there are MANY 10 bolts in MANY different ring gear sizes from 7" to 9" and across at least 3 different brands. Which causes a lot of confusion to those who really don't pay attention to "details".

Anywho............

So here it it.............

That width has to be given up somewhere if you are going to keep the stock A-Arms and shock mounts, steering mounts etc etc.

You need to shorten an axle on one side OR you need to move the diff over and shorten it on the other side.

AND-

Because it's wider - it's also taller, which means it has to be mounted lower to avoid the oil pan. Which means you need to re-do the mounting system.

Hope that helps

 

[MTUH3]

I stopped persuing one possible solution to help get a bigger diff in the front. I spoke to the guys at Moroso a while ago about a dry sump system for the I5. They were fairly confident it could be done, the trick out be the rear of the engine and transmission. It may also the front of the oil pan to be thinned up enough for the diff to fit. However, this is not cheap, I think it would have been $1000 - $2000 between the pump, lines, and other parts, and the fab time to make a new pan.

Also, I was not sure if the parts would carry over if I ever decided to swap motors, this is only on the table if the I5 takes a poo on me.

How about this option, could you incorporate a body lift and raise the drivetrain? New motor mounts, Transmount, Tcase mounts? Again probably cost prohibitive. But both options you could do in stages over a year or two to help.

 

[bebe]

Ok - I'll play

You can, but you would still have to custom mount a diff that's larger. You still have to have a shortened axle....

BTW the stub shafts/flanges are the easy part.

Also, the H3 shafts have 2 male ends, you would have to customize a diff to accept the male end of the h3 shaft, which is a lot more complicated that using a flange, ditching the H3 shaft and using a Chevy 1500 shaft which has a tripod design as well.

 

[bebe]

The new crossmember he made probably hung much lower

Diggers did not require a custom cross member - but he did have to customize the skid plate because the diff cover poked through

 

[06 H3]

ok well then how about this?

The only reason I want the H3 halfshafts is because its a massed produced part. I dont want downtime waiting for custom parts. A stub shaft with a flange is acceptable to be custom but I do not want custom halfshafts, I want mass produced. With that said I never thought of the wider housing being an issue. Now that you brought it up it makes total sense. Instead of using an H3 shaft on one end and a custom shaft on the other why dont we use H2 shafts like you did. There stronger also...Minus the strength, a plus of the H2 shaft is the length, its 21 11/16in long while the H3 shaft is 24 13/16th in long so its a tad over 3 inches shorter. With the shorter shaft you can then compensate the wider diff, in fact it may be too short but then you can compensate with the longer tube on one end. Not sure how feasible that is because the H2 flanges are bigger and may interfere. So does that sound at all possible? The goal for me is to keep the rancho kit as my subframe, stock UCAs and LCAs (might use custom if thats the only option but preferred stock) I am open to different mounting but dont wanna go with a chopped subframe/crossmembers. My issue with that is lets say I blow an axle and have issues setting up another one and need to temporarily go back to stock I want to do that, even if that means I would have to gear up the rear axle back to 4.56. I dont want this axle deal to be a never go back type deal.

I know its a lot to ask for and am open for custom parts but it all depends what has to be custom. So I guess the best question to ask initially is if an H2 halfshaft interfere with another component?

 

[MTUH3]

Knowledge increase to 0.1% This is great discussion.

 

[06 H3]

Diggers did not require a custom cross member - but he did have to customize the skid plate because the diff cover poked through

http://www.hummerxclub.com/forum/viewtopic.php?f=25&t=9933&start=75

Page 6, custom crossmember.

 

[06 H3]

Knowledge increase to 0.1% This is great discussion.

LOL, We can break it down for you if you need us to! I didnt know half this **** just a year or two ago. I sit online reading about this stuff as much as possible.

 

[MTUH3]

I think I just need to sit down with a few of these and start tinkering.....

Looking at the pics above, is the oil pan the limiting factor, or something else I don't see?

 

[06 H3]

I doubt it for this application as it worked, Bebe said that 4digr didnt use a custom crossmember but this was the crossmember he used, it isnt stock and I wanna use stock crossmembers if possible or if we cant switch back to stock options without too much trouble.

 

[bebe]

http://www.hummerxclub.com/forum/viewtopic.php?f=25&t=9933&start=75

Page 6, custom crossmember.

I totally forgot about his square tube and u-bolt :giggle:

 

[bebe]

ok well then how about this?

The only reason I want the H3 halfshafts is because its a massed produced part. I dont want downtime waiting for custom parts. A stub shaft with a flange is acceptable to be custom but I do not want custom halfshafts, I want mass produced. With that said I never thought of the wider housing being an issue. Now that you brought it up it makes total sense. Instead of using an H3 shaft on one end and a custom shaft on the other why dont we use H2 shafts like you did. There stronger also...Minus the strength, a plus of the H2 shaft is the length, its 21 11/16in long while the H3 shaft is 24 13/16th in long so its a tad over 3 inches shorter. With the shorter shaft you can then compensate the wider diff, in fact it may be too short but then you can compensate with the longer tube on one end. Not sure how feasible that is because the H2 flanges are bigger and may interfere. So does that sound at all possible? The goal for me is to keep the rancho kit as my subframe, stock UCAs and LCAs (might use custom if thats the only option but preferred stock) I am open to different mounting but dont wanna go with a chopped subframe/crossmembers. My issue with that is lets say I blow an axle and have issues setting up another one and need to temporarily go back to stock I want to do that, even if that means I would have to gear up the rear axle back to 4.56. I dont want this axle deal to be a never go back type deal.

I know its a lot to ask for and am open for custom parts but it all depends what has to be custom. So I guess the best question to ask initially is if an H2 halfshaft interfere with another component?

You can ask all you want - but if it's not possible you will need to adjust your expectations and parameters of the project (free life lesson...on me ) You are not always going to be a broke College Student!!

The shaft on the H3 is long because it's male. You have to add the stub that fits into the axle and the H2 axle shaft together to be accurate. They are a very different designs. The H2 Axle is designed for a clam-shell, not the traditional pumpkin style center section.

You can use them but you can't compare them. Different design, application, tolerances etc.

The H2 Shafts are produced for every GM 2500, 3500 trucks, suv's and van's - there are hundreds of thousands more made for the H2 than the H3 platform of "1".

We made the diff as narrow as it possibly could be and still be placed in the same general location.

What you need to do is take the H3 gayness (inside joke) out and then measure total width from the flat side of the outer CV where it fits into the knuckle (not the stub) on the passenger side to the opposite surface on the driver side and come up with an over all length. Remember when you do this that the axles need to be level, and that they be in the center of their plunge.

Once you have done that measure each side from the same point on the center of the diff to the CV outer flat surface with the axles level and the plunge centered.

What you are looking for is an accurate passenger side measurement, drivers side measurement and over all measurement.

THEN grab yourself a D44, 2 H2 shafts, some Dutchman set 20 bearing retainers and some stub shafts. At that point the goal is to "tinker" with the D44 with measurements making sure your stubs get proper engagement in the differential, and that you compensate for for the bearings, retainers and stubs in the length of each side as well as the over all. Same thing - measure from flat surface of the outer CV with level CV and the plunge centered.

Do this until they match - then figger out how to mount it and not bash the steering rack, cross member are easy. The only thing you should be worried about being "Custom" are items that can stop you from moving forward. Custom mounting and bracketry can likely be repaired on the trail, or welded up when you get home.

Easy as Pie :wink:

The only thing we contemplated and did not follow through with was the Ford TTB center section. It seemed that cutting a straight axle saved us a lot of fitting a fiddling with axle tubes. Could it have ended up narrower? maaaaybee. It might be worth looking into.

 

[MTUH3]

Imagine the 1 up mushroom from super mario. 0.2% Great thought process Bebe

 

[06 H3]

lol, Even though that crossmember isnt an engineering marvel I just had to make sure you knew it wasnt stock, Im sure the dimensions are nearly identical but still, its custom! :wink::shifty:

Alright sounds like a plan. I may PM 4speed then and get an empty AAM-7. Just one for mock up purposes. I dont wanna take mine out then put it back in then back out...Now I am kinda pist I let my buddy take that broken AAM-7 I used to have. I NEVER throw anything away but he needed some money and scrapped it.

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)

I am open to modifying and changing my plan around, I have a feeling I will have to do that but you might as well start with your "perfect little world, everything works the way you want" scenario first.

So, this is my new project after I get that 4:1 installed. First things first, start gathering parts then we will continue on the list of stuff to done.

I will pick up 2 H2 halfshafts, an axle (D44) any D44 from under any heep? An AAM-7 for mockup and measurements and an open mind.

With that said lets talk about axles, I know I am being picky here but why a D44? Should I still try the 10 bolt or go with that, or try the TTB? If no one has had luck with the TTB should I even bother? Keeping it simple is better. This will be my first custom axle build. I can build up existing axles and stuff but I am new to this. Its kinda exciting.:woot:

 

[06 H3]

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?

 

[4speedfunk]

None of this "will it fit or will it won't fit" conversation matters. You make it fit! You simply chop the 10-bolt to match the same length as the AAM-7. The idea is to get rid of all the custom stuff....crossmembers, half-shafts, stub axles, blah blah blah. If you gotta do all that, then I think most guys will be OUT. This thread is how to do it and keep it simple. So are you ready for the missing pics? Here they come! This is a brief rundown of how Blackbear did it...

First. Grab any GM front 10-bolt. These are all passenger-side drop and low pinion. Usually 2.73 or 3.08 gears...


Gut it. Clean it. Throw it on a band saw and cut the ps leaf spring mount off the casting. Leave a 1/4" or so....


I would mill that cut face, and make sure its 90-degrees to the axle shaft. Then fab and weld-on a steel cup to hold the stock H3 roller bearing and CV-seal. The bearing and seal can be robbed from the passenger-side of the AAM case. The roller is needed to support the inboard end of the CV joint. The seal keeps your oil inside where it belongs...


Next...grab a hunk of steel and fab a plate that mimics the ps face of the AAM-7 pumpkin. This is where the stock mounting ear bolts to the side of the case. You'll want to over-bore the center hole slightly to go on around the cup above...


Weld that sucker on. This completes the passenger-side. Here you can see the H3 CV seal...then the H3 roller bearing...then the 10-bolt carrier bearing...then the splines of the 10-bolt carrier (which match the splines of the AAM-7). Its critical to match the depth of these components, as they sit in the AAM-7. This will insure that the CV-shaft sits in the same exact position when plugged into the new 10-bolt. You might have to carve a slot on the ID of the carrier splines, so the snap-ring on the H3 half-shaft has a groove to "click" into...


After you have passenger-side done...test fit it against the AAM-7, and line-up the ps ends of both axles. The drivers-side tube can then be cut to match the same total length. I notice some discussions about it "fitting" under the truck...and you should certainly check this. However, I don't think its as big of a deal as you think. Obviously, the pinion centerline will be sitting an inch or so further inboard, and the critical issue is oil-pan clearance. Front driveshaft angle is a non-issue...I don't think you're moving it enough to matter. So just make sure the pumpkin clears the pan. A Rancho lift would help this issue TREMENDOUSLY, and I don't even think it would be close. Unlike Bebe's D44 long travel (which required the pumpkin to be shifted closer to the center of the truck)...the goal on this build is just the opposite. You want to keep the pumpkin as far to the ps as you can, because you're trying to re-use the stock half-shafts. The 10-bolt's driver-side axle tube can be trimmed accordingly, and thats the next step.

Now for the drivers-side. This might be a tad overkill...but Blackbear fabbed an adapter cup. The axle tube fits into one end and the H3 coupler bolts to the other end. Not sure I buy this idea but, that's what he did. I was thinking something a tad less complicated...simply a plate welded to the end of the 10-bolt tube. Regardless...the goal is the same...to mimic the end of the stock AAM-7 tube...


Check the axle against the AAM-7 again, taking into account the extra length of the adapter cup. Chop it. Weld the cup on. Bolt the stock H3 coupler and mounting ear in place...and TAH-DAH!....


The only thing not addressed here is the internal stub shaft. It might be possible to use the stock AAM-7 one but, it will probably be too long. Even so...its a very simple part to make. This is a simple floating shaft that connects the diff to the coupler on the drivers-side. It uses the same splines on each end. Depending on where the new pinion sits compared to the stock one...it might be possible to trim the stock shaft and re-use it. Also not addressed is welding a mounting ear onto the snout of the 10-bolt casting...a relatively minor task compared to this. I never saw this axle installed, and I don't know what ever happened to Blackbear or his axle....so from this point on, its a mystery.

In the end...the goal is to make a 10-bolt that has the same exact mounting points as the AAM-7. It has the same exact seals, splines, and receiver bearings for the H3 half-shafts. It will be slightly taller, slightly longer (front to rear), and the yoke will sit slightly further inboard. Best of all...its got an 8.5" ring gear...you can stuff some 4.56s and a locker in there...and its not a bolt-together, piece of crap, aluminum joke. I think this is a very do-able, feasible mod. I don't even have an IFS in my truck anymore...but, I'm very intrigued and wouldn't mind playing around with this swap. Its a much simpler swap than Bebe's, and a much easier swap than Digger's. You literally ONLY deal with the axle....everything else (torsion bars, rack, crossmember, A-arms, half-shafts, blah blah)....it all stays stock. Its not extreme...but it is very user-friendly, and no doubt a huge improvement.

 

[MTUH3]

Well done 4speed. Can you go bigger than 4.56 is this axle? If not I would look for a CI stock one

 

[atvspeed4]

Yes you can. Any ratio available for the rear you can get for the front. I think down to 5.38.

 

[Schwarttzy]

Man having a Eaton E-Locker, or better yet a Tru-Trac, up front would be nice... after sleeping on the idea, this is starting to seem like something I really have to do. I wouldn't completely mill out a part to mimic the passenger side of a AAM-7, because it shouldn't be any trouble to have those parts laser cut for cheap, and not to mention a lot easier. I have a buddy that could easily mill the shaft in the tubing down to size... this is really looking promising...

My only question, and think this was addressed earlier, are the axle shafts currently in the AAM-7 have the same spline count and diameter as a 10 Bolts (or possible a very particular 10 Bolt)?