New info on the Front Diffs

[HummerNewbie]

Originally posted by cestwick:
I used to build and race 4X4's in the mud and clay of florida ...

Thanks for the input and welcome to the forum. Now I have a question for you. Where the hell is there to wheel in FL?!?!

Not looking for mud runs but looking for good placed to get some all around wheeling fun in. I know there are more than a few of us that would like to know.

[f5fstop]

One question for Neo and Bebe, did you have traction control turned Off?
Also, was a front wheel in the air, and then it hit rock, or were both on the ground when the axle took a dump?

[NEOCON1]

hey f5 , we were in low with rear locked tractin cotrol off message is always shown for me when in 4 low we were BTMing with all four tires on the ground .

thanks for the input on all this .

[FormerJeeper]

Sounds like the front diff is as weak as ARB were claimimg.

Can one say solid front axle swap?

-C

[cestwick]

Thanks for the welcome Newbie. Most of what we did was mud runs but when we went out to play we used to camp and wheel in the Oceola national forest. Find a campsite, pick a trail and see where it goes. Obveously not as good rough stuff but we had fun. I had a 79 Blazer, 38" swampers 383 stroker and 4:56's. It would do a 200' mud hole in 5 seconds.

[Sewie]

Originally posted by NEOCON1:
hey f5 , we were in low with rear locked tractin cotrol off message is always shown for me when in 4 low we were BTMing with all four tires on the ground .

If mine broke when I think it did, I was doing the same thing. Only difference was I was on a dirt/gravel ledge, not on slickrock.

BTW, I got my truck last July, around the same time as Bebe and Neo.

[HummerNewbie]

Originally posted by cestwick:
Thanks for the welcome Newbie. Most of what we did was mud runs but when we went out to play we used to camp and wheel in the Oceola national forest. Find a campsite, pick a trail and see where it goes. Obveously not as good rough stuff but we had fun. I had a 79 Blazer, 38" swampers 383 stroker and 4:56's. It would do a 200' mud hole in 5 seconds.

Thanks, I have looked into going to Oceola.

[HummBebe]

Originally posted by f5fstop:
One question for Neo and Bebe, did you have traction control turned Off?
Also, was a front wheel in the air, and then it hit rock, or were both on the ground when the axle took a dump?

Yes.
When the truck is in 4lo lock with the rear locker on, the Stabilitrak system is turned off. Both of my wheels, front and rear were on the ground. I was essentially crawling up when mine spun.

[HummerNewbie]

Originally posted by Alec W:
You have 35s too if I am not mistaken?

I have my opinion and think the H3s drive train is weaker then the input power vs. output resistance. But… I wonder if 35s is what’s making the difference.


I guess time will tell us.

Oh sure, just repeat what I said

[Sewie]

Originally posted by Alec W:

You have 35s too if I am not mistaken?

Not yet. But I had planned on getting them before going to Moab in August.

[f5fstop]

I personally cannot go into great detail on this subject. I can say that there are very few reports of broken front diffs similar to that in the photo from Bebe.
I believe, traction control is active until it is manually turned off. However, stability control is deactivated automatically when the transfer case is shifted into 4-wheel low lock. These are two different systems, even if controlled basically by the same computer.
However, if no one turned the TC off manually, then the TC was operational, and that solves that question.

[PARAGON]

It's apparent that there are is not some widespread issue with the front diffs. What's sort of wierd is that there were probably other things that Bebe and Neo did that one would think would have popped the ring long before they made it to the stairs that day.

I think someone on one of the threads probably hit on the likely issue. It sounds like maybe there could be a ring or two here and there that was not "hardened", or whatever the process is, to the degree others are and to where it should be.

I doubt we see this occur very often.

[ketcat]

I don’t know if the gears were hardened correctly or not but I do know this has happened more then we have discussed. I can’t be specific but I heard about a couple of issues in the PHX area back in September.

People might not like me for this but I think the differential is too small. We are talking about a 4900 lb vehicle with 33” to 35” tires and a 56:1 to 69:1 crawl ratio. That’s a lot of traction, weight and torque multiplication for a 7.2” ring gear to handle.

A Dana 30 which is larger and is probably stronger than the differential in the front of an H3 is marginal in a TJ with 33’s. That’s why Rubicon’s have Dana 44’s front and rear and they run 31’s from the factory.

Someone mentioned SAS which is what I’m thinking although I’m not sure how feasible it is. High pinion Dana 44, 4 link and coilovers.

I love my Hummer but am not going to be left stranded in the Mountains. I'll fix the problem or get an H2 or H1 which I am seriously considering before I walk home. I can fix a tie rod on the trail but not a differential.

[PARAGON]

Originally posted by ketcat:
I don’t know if the gears were hardened correctly or not but I do know this has happened more then we have discussed. I can’t be specific but I heard about a couple of issues in the PHX area back in September.

People might not like me for this but I think the differential is too small. We are talking about a 4900 lb vehicle with 33” to 35” tires and a 56:1 to 69:1 crawl ratio. That’s a lot of traction, weight and torque multiplication for a 7.2” ring gear to handle.

A Dana 30 which is larger and is probably stronger than the differential in the front of an H3 is marginal in a TJ with 33’s. That’s why Rubicon’s have Dana 44’s front and rear and they run 31’s from the factory.

Someone mentioned SAS which is what I’m thinking although I’m not sure how feasible it is. High pinion Dana 44, 4 link and coilovers.

I love my Hummer but am not going to be left stranded in the Mountains. I'll fix the problem or get an H2 or H1 which I am seriously considering before I walk home. I can fix a tie rod on the trail but not a differential.

From all accounts you can count on your fingers and maybe toes how many times this has occured throughout all of testing and the thousands and thousands of vehicles that are out on the road now. If it was a stress reason, it's likely you would see the rings shattering. With the type of damage occuring it leads to a flaw in the gear itself.

This was not a grenading of the diff, this was spinning teeth off and is a completely different animal than what is normally seen.

A Dana 60 up front won't make any difference if the gears aren't properly hardened due to some impurity in the process.

I will promise you this. You do a SAS and get into other mods to do wheeling and you WILL be stranded because you are going to break something. It's just the nature of wheeling and you don't have the R&D budget that GM does to figure out what works and what doesn't at the cost of breaking things.

Blowing the front diff does not end your day. If you can do a SAS and fix a tie rod then you should be able to pull half shafts and the front driveline and drive it out in rear drive only.

[NEOCON1]

there are alot of opinions going around . one thing is anyone not with us or not familiar with golden stairs are thinking we were just driving . these steps were vertical and waist to chest high . no one should ever try anything close to this alone . the only trucks we saw were rock buggies and seriously modded jeeps . it is rated the third hardest run in the moab bible this trail has broken 1's 2's an 3's now

loaner white 3 with a little bling

[hmrlvr]

loaner white 3 with a little bling

LMAO
come home soon

[NEOCON1]

i dont want to come home man i want to get back to moab ASAP that place is amazing you gotta come with us in AUG.

[PackerFever]

August??? Holy Crapoli!

Its like the hottest time of year. Hot Hot Hot.

[HUMTECH]

Correct, an H-1 uses esentially an AMC model 20, actually A very strong differential just got the bad name as you said the 2 piece axles were the problem. A model 20 has A 8 7/8" ring gear which is only an 1/8 smaller than A ford 9" just doesn't have A pinion pilot bearing to steady the pinion gear like the 9". As for using A lower gear ratio to try to increase strength is backwards. the lower the ratio the smaller the pinion gear gets and creates A new weak point but at the same time requires less input torque to rotate the tires so it's kinda A catch 22 situation.

Originally posted by ketcat:
Just my 2 cents.....

4.88:1 with 35's puts you back to about stock with 33's so that sounds good. Problem is the lower (higher numerically) the gear the more teeth which equals less metal per tooth so in theory with all things being equal a 4.88:1 is weaker than a 4.56:1.

As I recall the H1 uses an AMC model 20 differential which was used in CJ’s etc……and not known to be the most durable differential in the world especially the two piece axles. The reason it holds together in an H1 is because they run a 2.56:1 or 2.73:1 gear ratio and multiply at the geared hub.

My opinion if people are breaking gears finding stronger ones is a good idea but I’m not sure going to a lower gear is the best idea. At least if it’s stock the dealer will warranty it for 50k miles.