New info on the Front Diffs

[ketcat]

Again just my opinion......

4.88:1 would give you more torque and get you back to about a stock overall ratio if you have changed out the 285's for 315's. I like the idea of a 4.88 or maybe even a 5.12ish ratio with 315's. On the other hand there is the possibility that a lower ratio (higher numerically) would be easier to break.

In either case I personally would wait and see if more differentials break because it's under warranty now and once you install aftermarket parts the warranty is gone. If it ends up being a bad gear issue and not related to the differential itself then upgrading is probably a safe beat. If on the other hand it's related to the differential I would not want to change anything.

[cestwick]

Hello all..new to forum first post but I thought I would put in my 2 cents. I am a Hummer tech in Sioux Falls SD. We have only had one H3 blow a front diff here. Actually happened on our Demo out on the test track. Truck had 800 miles on it. Got stuck in the mogals (snow and mud) we hooked a chain and pulled it out. Very little if any wheel spin but it was in 4low and as soon as front wheels got to solid ground all the torque was at the front and it shaved the teeth right off the ring gear. Last Dec. I was in South Bend talking to several other techs and at that time the only bigger things they were fixing was the front diff's. Like has been eluded to previously I believe the problemm is week material in the ring gear. I used to build and race 4X4's in the mud and clay of florida and we had trucks with a 1000 hp that never broke ring and pinions.

[Bully13]

Originally posted by PackerFever:
August??? Holy Crapoli!

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

Yeah! Gonna be great! Getting stuck and then sweating up a storm. Watchout for desert colored H1s

[PARAGON]

Originally posted by cestwick:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PhilD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by cestwick:
I'm not sure if any of you have ever pulled a front shaft on the H3 but it isn't the simplest job to do.

Even easier if you've blown a CV.

You basically have to pull the front knuckles off to get the shaft out.

Can't you just disconnect the tie rod and swing the knuckle around. That is what you do on a H2, but I haven't looked at a H3 close enough to see if it would be the same.

FWIW The H2 axle nut is only torqued to 155 lb/ft and requires a 35mm socket. </div></BLOCKQUOTE>

No you can't. On the H2 you have the luxury of a halfshaft that bolts to the diff. H3 the shaft goes into the diff housing. Not enough room to turn knuckle and pull shaft. </div></BLOCKQUOTE>sawzall?

[cestwick]

Originally posted by PARAGON:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PhilD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummBebe:
I don't think we can do that on the three's, has something to do with the computer thingy.

Bet you can, even if you have to start pulling fuses until it works. </div></BLOCKQUOTE>

Ok, we discussed that on the trail with the HUMMER mechanic.....I called him 2 seconds after I was off the trail....to order parts :-)

He mentioned that Stabilitrac would/could prevent the whole vehicle from operating if disabled.

That was honestly the first thing I thought of, I just wanted to go home </div></BLOCKQUOTE>You can simply pull the half shafts and front driveline without pulling any fuses.

All of the traction control, Stabilitrack and ABS runs off of the wheel speed sensors and maybe a sensor at the output shafts of the t-case.

If you are moving the wheels are are all turning and the computer doesn't know if power is going to the front or not. </div></BLOCKQUOTE>

I'm not sure if any of you have ever pulled a front shaft on the H3 but it isn't the simplest job to do. You basically have to pull the front knuckles off to get the shaft out. Also I'm not 100% positive about the H3 at this time but I do know that on most GM 4x4's the outer joint assembly is what holds the hub/bearing togather and is actually suposed to be tightened to 191 ft lbs. I have seen where the drive shaft nut wasn't tightened and the bearing went out in a very short period.

[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.

[ChasH3]

Originally posted by ChasH3:
Bebe my stabilitrac shut off the other day while I was driving on the Freeway.. I even got a message saying it was off and needed service and the indicator light on the 4x4(All wheel drive) button was off... The H3 drove fine. Then after I got off the freeway and was able to turn the H3 off and back on everything worked fine... Weird.....

I was just thinking that since the stabilitrac was shut off that maybe there is a way to disconnect it without preventing the whole vehicle from operating and/or disabled like the mechanic stated....

[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:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PhilD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NoMoGMPG:
the 'fix' would be a stronger material.

That is good advice, stronger gears of the same ratio is a far better idea than the dealers on of running 5.13's. </div></BLOCKQUOTE>

I would have to vote for stronger gears too. From surfing through this thread and many others, my first glance is a hardening problem. But I will see what I can find out...unofficially. </div></BLOCKQUOTE>

Thanks, I appreciate everyone's opinions on this.

Going from a 4:56 with 35" tires to 4:88's with 35" tires, may not make that much more of a difference. But I appreciate the comments. BebeRhino is my daily driver, however most of it is city, or congested freeways. No real need for high speeds.

As long as the Yukons are a stronger material, I may still look at this as a viable option.

Someone has to be a guinea pig

[PackerFever]

August??? Holy Crapoli!

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

[f5fstop]

Originally posted by PhilD:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by NoMoGMPG:
the 'fix' would be a stronger material.

That is good advice, stronger gears of the same ratio is a far better idea than the dealers on of running 5.13's. </div></BLOCKQUOTE>

I would have to vote for stronger gears too. From surfing through this thread and many others, my first glance is a hardening problem. But I will see what I can find out...unofficially.

[PARAGON]

Originally posted by cestwick:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by f5fstop:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PARAGON:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by HummerNewbie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PARAGON:
...But there might be a relationship to the two trucks through the front ring/pinions because their build dates are fairly close together...

I agree completely especially since there are now three since HI's has to be replaced. I would really like to see some investigation into this since the three vehicles that I know of with this problem were all purchase right at the same time. Of course any one of them could have been sitting on the lot for a while but I really think this needs to be looked into. Based on VIN numbers I would think it would be fairly easy to check the lot numbers for the gears in each truck. If the lot numbers are all different then that probably counts out a hardening issue but if they are all the same it would narrow down the possible problems in my book. </div></BLOCKQUOTE>I promise, it's being investigated. </div></BLOCKQUOTE>

Oh yes, it is being investigated, and maybe some more.

A few notes on other comments.
The axles already come with synthetic fluid, and the fluid is not the problem. The problem appears to be hardness.

Does GM put the minimal parts in the vehicle? Yes and no. The specs on these axles was high, whether or not AAM is cutting corners remains to be seen.

They won't put the largest axle available, for that would be a waste of money, but they won't put the weakest either; especially in something they know will be off-roaded by a certain number at places most would mess their drawers thinking about.

All I can say on this board is that as the numbers of destroyed axles rises, and as of yesterday, there were very very few, people will start asking questions. The three that we have on this board have not hit the warranty reports until the repairs are completed, and the dealer submits the labor op for payment. That is how the warranty numbers are run by engineering.

I can say, that some are raising their eyebrows with just the one photo I sent to engineering and mentioned there were two of these on one day. Tomorrow, I will let them know there are three that I personally know of.

If they jump on this like the cylinder head issue, it will not take many more to explode. The cylinder head issue was researched and the head re-designed with an extremely low number of failures; especially considering the number of these engines are on the road since '04.
I can't say for sure, since I'm low on the totem pole, but I would bet if there is a problem found, there would never be a recall, due to the low numbers of axles that will be replaced. However, I would bet a lunch, that if a problem is found, new axle specs will be established, and these new axles will be put into production, and shipped to service parts, so that the replacement axles, if needed, will be the stronger axle.

That is all I can really say on the matter; except please stop breaking your H3s. For some odd reason, when something big happens on one of these vehicles, I get pushed into the middle to help the situation, and I'm already busier than a one legged man in an ass kicking contest. (I'm trying to be funny... ) </div></BLOCKQUOTE>

f5fstop
I am sure we still have the front diff I pulled out could you use a pic of it as well? I know it looked almost exactly like The pic on here. </div></BLOCKQUOTE>you damn skippy

get some good ones too, like from an angle and chit.

[ketcat]

I’ve been wheeling for a long time, have had a lot of 4x4’s from a variety of manufacturers, work in the auto industry and have seen a bunch of broken differentials. I’m not anti Hummer and or pro Jeep in fact as I mentioned the Dana 30 (and Dana 35) are probably not up to any type of hard wheeling with larger tires even when upgraded.

You are correct defective gear's in a Dana 60 or what ever can cause a failure. From what I have read we are all guessing what caused the problem, at this point it‘s unknown why they broke.

As I said before the front differential in my opinion is rather small for extreme four wheeling in a 4900 lb vehicle with 33”+ tires and a 55:1+ crawl ratio. Which is why I am considering an H2 or H1. Not that they don’t break, they do.

Pulling a driveline and half shafts is no big deal but I would still rather replace a tie rod. BTW I was not referring to replacing a tie rod on an SAS H3 or saying I was going to do one. I’m sure some off road shops will be or already are working on that. I was saying that I am thinking of getting an H2 or H1 and that I would rather bent a tie rod than blow a diff.

As for the type of terrain they were on when the diff’s broke I’ve been to Moab, in fact my first 4x4 trip with the H3 was to Moab June of 05. I’ve not been on the Golden Stairs but have heard about the difficulty and am sure you could break just about anything on that obstacle. I’m certain the H3 can go off road a bunch and never have a problem. I’ve been on a bunch of trails in AZ, CO, UT and ID with out incident. I'm not anti H3, I love mine!

[evldave]

chances are if you have access to a welder in the field, you've also got access to someone that can pull half-shafts & DS and you can just drive out in 2WD.

I think you'd have just as much luck with bubble gum vs JB weld on ring gears...

[PARAGON]

Originally posted by Alec W:
All this is great if you have the time and tools, however with only 2 wheel drive you can’t drive out from the middle of Golden Spike anyway. Sometimes it’s better just to get the tow strap out and drag a dead truck to the shop

I'm guessing Golden Spike is not the only place something like this could occur and some people that own the vehicle were interested in know what possibilities were out there.

Doing the above can get you 500 miles back to home on the highway instead of stranded in some small town with a single mechanic or a large tow truck bill.

[HummBebe]

Oh and PS....

The first Rule of Wheeling, is to never wheel alone.

[HummerNewbie]

Originally posted by f5fstop:
...my first glance is a hardening problem.

Here is a shot in the dark but how close were the built dates on Neo's and Bebe's rigs? Could it possibly be that there was a problem in the production/hardening of these gears and by dumb luck, they both had gears from this batch? Sorry Bebe and Neo, just looking for a silver lining for the rest of us

[NoMoGMPG]

Originally posted by PARAGON:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by CO Hummer:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PARAGON:
It's looking like this is not systemic problem. Already, it appears that some ring gears can possibly make it through the system into the front of the trucks without proper hardening for the harder type wheeling that Golden Spike requires.

I don't know.....that seems like too great a coincidence that both trucks would have the same metallurgic problem, both would experience the same effect on the exact same obstacle, etc. </div></BLOCKQUOTE>Well, I really, really don't like coincidences and I agree. But there might be a relationship to the two trucks through the front ring/pinions because their build dates are fairly close together.

Not knowing the entire process at the gear manufacturer, it's really hard to speculate further. But they are very into this potential problem and if it was systemic then more than the handful that have shown up would likely have occured.

I have to also question why Golden Stairs. I wonder if the front diffs heated up from the hard wheeling up to the stairs and that changed it's properties some. Undoubtedly, some of the other days would have stressed the diff as much as the stairs did at that time. </div></BLOCKQUOTE>

For some reason, the Stairs claim Hummer axles. We broke a halfshaft on Wednesday when tire spin/hookup occurred. Dan Mick told me once that more axles and t/cases are claimed on that obstacle than any other on the Spike.

Dave

[Cranky Steve]

Couple tips. Avoid wheel spin on the rocks. If your spinning, your air pressure is too high. Pretend there is a raw egg between your foot and the skinny pedal. Spinning in the dirt does not shock the drive line like it does on the rocks.

A front locker really helps when used correctly.

Switch to high quality synthetic gear oil. Redline is a good choice, and has a broad line up to cover whatever GM calls for. Synthetics will allow the diffs to run cooler, and maintain lubrication in all temps much better than regular gear oils.

As mentioned, increasing Tire diameter can warrant going to a lower gear. There are charts on the net that can help you figure which gear ratio match up correctly.

Yukon gears are Randy's house brand, which means the box may contain gears from several manufacturers. The could be Dana (OEM, good stuff), US Gear (Excellent Aftermarket), etc.

Stay away from Genuine Gear, it's junk.

Lastly, keep in mind, that once you start really offroading, you will find the week links quickly. Not many current 4x4's are really bullet proof anymore like they were in the early 80's.

So, before you start mods, think it through, "Cause and effect". In other words, when you think about changing something, consider how it plays in the overall scheme of things, and make sure the rest of the players are matched.

I can't wait for someone to go for it on an h3 and put a Solid axle in front, Springover the rear, move the low hanging rear shocks, etc. H3's are definitely the right size for all trails!

[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.