Hummer H1 diffs....so why not?

[4speedfunk]

Many of us here on H4O have contemplated, attempted, and even completed (Bebe & Digger) IFS builds on H3's. We've all been down the same road and the same question keeps coming up over and over....What differential is the logical choice as a basis for an H3 IFS?

Well among the numerous answers, (ranging from hi-dollar aftermarket stuff to low-dollar chopped up stuff)...has always been the H1 diff. I actually stumble across a good many of these IFS pumpkins for sale....for very little money. They have lots of mounting points cast into them; they already have flanged stub-shafts; and they look to be really perfect for what most of us are wanting for our H3's. Many times this diff has appeared in conversations but, that usually ends when you realize that the H1 has portal axles that reduce the final gear ratio further, out at the hubs. This means that these H1 diffs come equipped with some pretty tall gearing (2.56 to 3.31)....useless for what most of us are looking for. And that's where this idea always seems to end.

So I hit a few websites today just for curiosity's sake. I found out that the H1 uses AMC-20 internals?....surely this can't be right? Yup. I have several Jeep-CJ guys that still run these axles, and I've never thought much of them. But perhaps the H1 casting fixes many of the issues the old Jeeps have. Other than the internals...its safe to say the H1 diff is nothing like an old CJ diff. So...digging further I found that most Hummer websites will offer the typical 2.56 to 3.31 gearing that any H1 guy would want. BUT...if you really dig, you'll find that the H1 diff can use the old Jeep 3 & 4 series carriers and gearing. Does this mean that lockers and 4.88 gears are available for the H1??? I had no idea. Here's one of many sources I have found that says this is so...
http://www.ebay.com/itm/Ring-and-Pi...Parts_Accessories&hash=item3a80550ffe&vxp=mtr

Now I'm curious...but I'm a total dumb-a$$ about the H1. Any H1 guys know more about this?

 

[SuperBuickGuy]

you mean beside the fact that it spins the wrong way?

 

[06 H3]

My question is if an H1 front diff would last in an H3...Sounds crazy right!?! But the H1 front diff lasts because of the portals. They greatly reduce the gearing without putting that stress to the diffs. Can an AMC 20 hold up in an H3? I dont know...

Im not H1 expert so I will gladly listen to the theories and thoughts.

 

[ArtHummer]

I know absolutely nothing about H1 and not much about 4x4 in general. But, I was thinking, if you bringing the H1 diff, will it also be possible to bring in H1's axles and hubs. Yes, it will require allot of cutting and fabing and yada, yada, yada... but just elaborating (would be awesome to have that extra few inches of clearance from the ground to lower control arm... :drool::evil: ).
Would be great to hear from someone who know the subject.

:corn::corn::corn:

 

[autumn walker]

But, I was thinking, if you bringing the H1 diff, will it also be possible to bring in H1's axles and hubs.

Those are the mucho expensive parts.

 

[MTUH3]

I sent a not to these guys a while ago. Not sure on cost, but have checked out some of their trucks... and WOW

http://www.proformance.com.au/



Info from them:

Our diff is 12" round, 10" Wide, with INTERNAL CV joints. The CV Joint faces are 4" apart.

 

[MTUH3]

Those are the mucho expensive parts.

Remember you need to relocate the brakes, as they are located under the truck by the diff, if you go with their hubs... or find a way to modify the hub assemble to fit a rotor and caliper

 

[06 H3]

those diff assemblies are crazy expensive MTUH3. I remember reading about them on pirate...around 20k IIRC.

 

[MTUH3]

I know.... Just pointing them out. I didn't even ask them what the cost would be :wink:

 

[06 H3]

o ok...lol if I win the lottery Ill buy a few.

 

[4speedfunk]

you mean beside the fact that it spins the wrong way?

I assume you're talking about a reverse rotation hi-pin arrangement? To clarify...a Hi-pin and a Lo-pin can spin in either direction. A high pinion does not spin "the wrong way"...its simply designed to run spinning in the opposite direction. If you think this is a problem...ask the untold millions of Lo-pin front axles (including the H3's stock AAM-7) that have been running "the wrong way" in every GM, Dodge, and Jeep from 1969 to 1991. I think I get your point, however: The two designs do require different tooth mesh patterns, and they are NOT interchangeable.

You raise a great question SBuick...are H1 AMC-20's hi-pinion? (they look like it to me) If so, then why do so many companies list the H1 as an application in their AMC-20 ring & pinion catalogs? Like I said...I don't know that much about the H1 version of the AMC-20 but, I got a couple friends that run AMC-20s under their Jeeps, and they are Lo-pin for sure. This is where my AMC-20 knowledge grinds to a halt. I really don't know that much about them (Jeep or Hummer). Like ArtHummer says...Would be great to hear from someone who knows the subject. I'm just throwin it out there.

Can an AMC 20 hold up in an H3?

That was my first thought. My CJ buddies can't wait to get their AMC-20's out from under their Jeeps. But, remember...the two are seriously different housings. Despite the portal reduction, I think the H1 AMC-20 must be a pretty robust diff to survive in a super-heavyweight military vehicle.

 

[atvspeed4]

One good point that SBuickGuy makes...are H1's hi-pinion?

If so, then why do so many companies list the H1 as an application in their AMC-20 ring & pinion catalogs?

Like I said...I don't know that much about the H1 version of the AMC-20. I got many friends that run AMC-20s under their Jeeps, and they are Lo-Pin for sure.

They are high pinion reverse rotation. The portals have one gear instead of two so that the rotation is corrected.

 

[4speedfunk]

Ahhh. Then something is amiss in the AMC-20 world of ring & pinions. The two designs definitely need different mesh patterns.

The portals have one gear instead of two so that the rotation is corrected.

No correction required. It's running in reverse because its installed backwards (with the yoke facing rearward) in the vehicle...like any front axle (hi or low pin).

 

[atvspeed4]

Ahhh. Then something is amiss in the AMC-20 world of ring & pinions. The two designs definitely need different mesh patterns.



No correction required. It's running in reverse because its installed backwards (with the yoke facing rearward) in the vehicle...like any front axle (hi or low pin).

Next time we are in the H1 Ill try to take a quick video. When the hummer is moving forwards and you look at the cvs they are turning counter clockwise. Its not like when we have taken a 10 bolt and tried to use it as a front low pinion.

From what I can tell its like they took a normal amc 20 low pinion and flipped it then made the appropriate oiling splash changes

 

[4speedfunk]

Got it. Weird.

So that means the H1 t-case is spinning the front driveshaft the wrong way? (compared to any other 4x4)

 

[atvspeed4]

Got it. Weird.

So that means the H1 t-case is spinning the front driveshaft the wrong way? (compared to any other 4x4)

lol no. The driveshaft is spinning the normal way, the diff is flipped and spins the opposite way and the portal hubs correct the rotation.

Here is a link to what the inside of a traditional portal hub looks like such as the H1s http://www.proformance.com.au/Portal_Hub.html

Here is a link to a portal hub that does not change rotation http://www.fourwheeler.com/how-to/t...on-portal-axles-dana-60-14-bolt/photo-02.html

 

[Bigunit]

Great discussion but really, who is going to spend the money to mod an H3 this way? Seriously, let's be practical - much rather spend my money if I ever get to the his point with my H3T and turn it over to someone like Dwaine to replace my suspension with a Scorpion suspension. If you have ever seen and compared what the Scorpion suspension can do & how it work vs. the HUMMER or H1 suspension, you would realize that there is no comparison and wouldn't be talking about putting an H1 diff and suspension on an H3. Point is, you don't know what you don't know. Time to really think out of the box. Hope no one gets butt-hurt with this opinion but I've decided to add and support another option to those thinking of spending their money on aftermarket suspension options for the H3/H3T.

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[SolidusJ]

Next time we are in the H1 Ill try to take a quick video. When the hummer is moving forwards and you look at the cvs they are turning counter clockwise. Its not like when we have taken a 10 bolt and tried to use it as a front low pinion.

From what I can tell its like they took a normal amc 20 low pinion and flipped it then made the appropriate oiling splash changes

This is right up my alley seeing I'm a 91B. The transmission spins counter clock wise to keep guys like me from walking off with them. The CV's spin backward and then into the hubs there are 2 gears the correct the rotation. Pretty much to rise the front end higher and keep the CV up high and safe.

No matter if the diff is front or rear you can put them ether end and it will work, trust me had a front end HMMWV blown off and I needed a rear diff in mine and it work with no problems.

A few years back me and Trailbraker was talking about putting a HMMWV diff in his T and the thought never left my mind... Yes the brakes mount on the diff but you can remove that bracket if you want. I'll see what I can do, when we clean out old motor pools anything that's trashed is yours if you want it and I knew I should have grab the few last ones I seen.:gaah:

 

[06 H3]

If you flipped an amc20 over you could solve that problem.

I agree with BU about portals and putting an H1 suspension under a 3. It's more dreaming and a ton of money and with that money you could probably do a custom job better but I personally need cheaper solutions. If you could flip an H1 diff upside down with its stock stub shafts I'm all in and I think that was the reason of 4speeds original point. Use the diff that's it.

 

[freeze]

That's assuming the oil gets distributed correctly upside down. Also just because it came from an h1 doesn't necessarily mean its well designed or stronger. I forget which forum it was, but someone posted that h1 CV shafts share some components with Camry CV shafts. The h1 components were definitely designed with the fact that torque is multiplied at the hubs in mind.

 

[silvrzuki77]

Great idea versus a a rich mans with deep pockets and no conecpt of money dana 80 thats over priced and a less than ideal suspension design as the scorpion. (Which was cool when it was designed, but outdated). 4speedfunk I like your passion into finding a good alternative and investigation.

I had a friend flip a toyota 3rd to high pinion and figured out how to properly oil it. Been running great for the last 4 yrs.

 

[PreferredChassisFab]

Reality Check .....
While the H1 is a proven, reliable platform for light/medium transport on semi improved, hard surface roads/trails, it has its limitations. The suspension/drive system is limited due to its roadability issues due to the portal design, and its limited suspension articulation both compression and droop.
The center mounted carrier with its inboard brakes, and the wheel end portals mounting and size requires space and structure not available in the H3.
The armed forces are looking for off-road capabilities improvements for the H1 to make it more off-road capable, largely for suspension and power.
This conversion will cost 10s of thousands of dollars, and improvements realized will be based on the installers modifications to the original H1 design. But the use of the H1 components will also import the H1 suspension/drive system non desired characteristics.
Any conversion is possible but the comparison of investment to reward needs a "Reality Check".
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[PreferredChassisFab]

Great idea versus a a rich mans with deep pockets and no conecpt of money dana 80 thats over priced and a less than ideal suspension design as the scorpion. (Which was cool when it was designed, but outdated).

As I said "Reality Check", but what the heck, we are all friends here....


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[silvrzuki77]

As I said "Reality Check", but what the heck, we are all friends here....


Sent from my C771 using Tapatalk 2

Hey Dwaine, sorry I wasnt trying to come off that way, heck I have a scorpion rc car from walmart that my kids still drive around! I even have polaroids pictures from that truck brand new that inspired me to build my tube buggy.
With all the KOH stuff and unlimited trophy truck stuff I've been helping with times have changed. I appreciate the fact people are still passionate to look at alternatives, versus dropping it off at a shop.

 

[PreferredChassisFab]

Hey Dwaine, sorry I wasnt trying to come off that way, heck I have a scorpion rc car from walmart that my kids still drive around! I even have polaroids pictures from that truck brand new that inspired me to build my tube buggy.

Yea............All Friends............
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