H3 with MAJOR drivetrain problems

[lugantom]

I have a 2008 H3 Alpha that I love, but, like an Italian sports car, the excellence of its design has been severely compromised by its reliability. GM and the dealership have been great, and even extended my extended warranty, but this latest failure has me scared.

Called dealership yesterday after major front driveline failure - severe clunk. I hoped it was just a half-shaft, but, after almost a week they dug thoroughly and told me yesterday that the front differential was trashed.

This is shocking to me because this H3 has seen VERY little off-roading. I asked the guy how that was possible, he thought maybe wheels spun on ice then grabbed pavement. I asked if it could be a sort of chronic failure, where it was weakened, then failed over time. He didn't think so. I told him there's no way it failed as he described - at the time of the failure, the truck was sitting on snow on top of grass next to my house. I spun the wheels in the snow, applied the brake so that I could stop the wheels and shift from reverse to drive to rock out of the snow, and I heard a crash and grinding.

So, a few questions:
1) Can anyone explain how a front differential can catastrophically fail in a truck that is spinning its wheels at low rpm on snow on top of grass?
2) How worried should I be? They are fixing it all on warranty, but if that front diff had failed at highway speed I could have completely lost control of the vehicle.

Any insights appreciated. I still love this truck, but I am genuinely worried about keeping it. GM has made it clear that this is the last warranty repair, so I am worried about my safety and about what else could still go wrong.

Here's a list of the fairly significant warranty repairs to date:
(2) separate wiring harness shorts that required multiple service calls to resolve
(2) transfer case failures
front axle half-shaft failure
door lock solenoid failure
burns oil
XM radio antenna failure

 

[alrock]

Moved this to H3 section - you'll get more answers from the members than a specific deep troubleshooting question from Mike.

Wear and tear on more suspect components like the rear pinion bearing and seal can lead to premature wear and tear (and failure) of the other components. Also, the crossmember bushing tends to fail even on street vehicles, leading to more abuse of the front diff while the bushing is unrepaired.

The failure of the diff (or half-shafts) isn't necessarily a result of the spinning itself, but the spinning that is suddenly interrupted. Taking a wheel that is moving at say 15 mph and is suddenly stopped by hitting pavement, another grippy surface or a firm application of the brakes creates a lot of torque and can easily break drivetrain components. "Normal" braking results in a much more gradual slowdown of the wheels but on slippery surfaces the change can be instantaneous.

For the other issues, I think more info is needed. 1 transfer case failure, while not necessarily normal, isn't unrealistic. The 2nd failure could have come from a poor rebuild, if they rebuilt it. Half-shaft - any vehicles with CVs like in these half-shafts can experience this type of failure. Door lock and antenna I would chalk up to small things that can fail in any vehicle.

How much oil is it using?

 

[Reloader]

Are they going to repair your existing diff assembly or replace complete unit with a new factory or a road proven ( aka used ) one? If repairing it I hope the tech takes the time to set it up right as warranty time doesn't pay diddly and it may get slammed back together. I used to work in a dealership and stuff would get fixed like that and if it came back , it would get blamed on defective parts. When ring and pinion teeth break off and get pulled through the gears, something has to give. The diff case and or the carrier could be bent or warped and if rebuilt will just fail again down the road.
It took them a week to figure this out? May be they just back burnered the truck and used it for fill in work but a broken front diff should have been a quick discovery easily verified by popping the front diff cover or just pulling the drain plug to find chunks and pieces of internals.
Where were the shorts in the wiring? Was there any previous damage in these areas.
And yes, how much oil is it using? My 08 Alpha with 86K on it will use a little if I don't change the oil till over 5K miles or so. And the rear main seal will weep a bit and then dry up for a while. While I don't agree , most manufacturers will say that a quart every 600 miles is acceptable if there are no leaks.
Could the transfer case failures just been a defective shift fork the first time? Mine is an early 08 and came with the plastic fork and was replaced with the metal one under warranty. This was real common and I have done several myself . Ill bet there are many more out there that are still bad but the owners don't realize it because they never get used in 4 high lock or low range. I had a trade in one time that was driven in 4 high lock for a long time as the plastic fork failed and would not let it release back to just 4 hi but the indicator lamp said it was.

Keep us informed as to the outcome.

 

[lugantom]

Little More Info on H3 Problems

You are correct on the delay - they back-burnered it. However, we all assumed any play was in the t-case. We were all surprised when they pulled it back into the shop and concluded that the front diff failed. I was not overly upset about the delay, as they have given me a nice loaner car. However, we're supposed to get about 6" of snow tomorrow, and I'll be in a FWD sedan, not my hummer!

As of now, they are waiting on parts, and are committed to a full rebuild of the front diff. No argument, all on warranty, so that's a blessing. One time on a previous failure we had a pretty big fight. I'm glad that was avoided this time. I also agree on collateral damage. During a brief conversation, the service guy did say that they have to replace multiple components that received damage due to the failure. I still don't have the details, but they are planning on saving the parts for me.

Oil burning - it uses a quart every 2 - 3K miles. Not terrible, but surprising. No observable leaks, so I suspect some leakage at the valves. Surprises me, because we have the same engine in the wife's Suburban and it has been perfect.

Main issue on the electrical problems was slow diagnosis. Guys on this forum have helped me realize which connections are getting wet, so at least I know how to avoid the problems in the future. Was no damage, just very poorly located connectors (in the wheel well on the frame).

I think you are correct on the T-case. They did one repair, then it was sticking in 4 lock, then did the second repair. I suspect they just didn't research all the Technical Service Bulletins and do the whole repair at once, or didn't do it correctly the first time. That one was tough, because it was an intermittent failure. Fortunately it happened RIGHT as I was pulling up to the service door, so I ran inside with the truck running and let the service guy come out and try to drive it. He could see that it was binding on the dry pavement.

I'll let you know what I hear. Again, I just can't believe that hard braking of a spinning wheel or slipping on ice and then grabbing pavement should ever result in a differential failure. I compared it to a neutral drop to the mechanic - I said rear axles would be failing all over the place if sudden application of torque at the wheel could cause a failure. By design, the ring and pinion should always go last, as their failure can be a serious danger to drivers and passengers. Given the known failures of the half shafts, I would just have assumed that a half shaft would fail long before a ring and pinion. I'll let everybody know what I find out when they're done and show me the parts.

It still blows my mind that this happened alongside my house on my lawn (covered by snow). It must be correct that the final straw occurred when the brakes grabbed the wheel and put that extra torque on the whole system.

Are they going to repair your existing diff assembly or replace complete unit with a new factory or a road proven ( aka used ) one? If repairing it I hope the tech takes the time to set it up right as warranty time doesn't pay diddly and it may get slammed back together. I used to work in a dealership and stuff would get fixed like that and if it came back , it would get blamed on defective parts. When ring and pinion teeth break off and get pulled through the gears, something has to give. The diff case and or the carrier could be bent or warped and if rebuilt will just fail again down the road.
It took them a week to figure this out? May be they just back burnered the truck and used it for fill in work but a broken front diff should have been a quick discovery easily verified by popping the front diff cover or just pulling the drain plug to find chunks and pieces of internals.
Where were the shorts in the wiring? Was there any previous damage in these areas.
And yes, how much oil is it using? My 08 Alpha with 86K on it will use a little if I don't change the oil till over 5K miles or so. And the rear main seal will weep a bit and then dry up for a while. While I don't agree , most manufacturers will say that a quart every 600 miles is acceptable if there are no leaks.
Could the transfer case failures just been a defective shift fork the first time? Mine is an early 08 and came with the plastic fork and was replaced with the metal one under warranty. This was real common and I have done several myself . Ill bet there are many more out there that are still bad but the owners don't realize it because they never get used in 4 high lock or low range. I had a trade in one time that was driven in 4 high lock for a long time as the plastic fork failed and would not let it release back to just 4 hi but the indicator lamp said it was.

Keep us informed as to the outcome.

 

[Reloader]

The one that I fixed that was stuck in 4 hi lock needed the sleeve/collar that the shift fork engages along with a new metal shift fork. The shift fork is such a common problem on these, I believe the after market is selling them now.

Dont forget fellow forum members that you can also get a replacement CV joint for the rear end of the front propeller shaft. I carry one for a trail spare along with a spare u-joint. Dorman makes it (or just repackages it) part no. 932-105. It also fits the Colorado/Canyons. I believe Amazon is the best price.

 

[Best4x4]

Sounds like the previous CV axle failures, and transfer case failures finally took it's toll on the front diff.

The 5.3L isn't actually burning oil in the normal manor. If it was you'd see smoke at startup or while driving. It's basically sucking it into the intake and then being burned that way. Not like it's slipping past the valves or piston rings. I know my Alpha does this (after going 5K my first oil change and being 1.5qt low). I use Penzoil High Mileage 5w30 now (was using Mobil1 Synthetic before), and I change the oil every 3K and that pretty much takes care of being 1-1.5qt low.

My Alpha has been great so far and I've now got close to 120K on it. The front end is clunking, but my upper ball joints are blown, and my lower ball joints aren't to far behind I'm sure. I have noticed the H3's chink in it's armor has to be the OEM front lower diff bushing.. On almost every H3 I've seen from 29K to 100K that bushing is busted. I replaced mine ASAP with the Scorpworks unit and it took care of the diff moving up/down nearly an inch (OD didn't have their kits available yet). Most IFS setups I've owned on 4x4's eventually all make their own little noises, but as long as everything is in good shape upper/lower ball joints, tie rod ends, CV Axles, Shocks, Bushings, and bumpstops they work and work well.

I'll be changing out the upper/lower ball joints, CV's, and getting it fully aligned soon. I hope that takes most of the noise out of the front end. I did some wheeling the other day and I get a lovely groan/pop from the torsion bar area, but after driving on the road for an hour it seems the suspension settled back down and the groan/pop is almost gone.

 

[lugantom]

I agree - had to be a chronic failure and the event when it snapped just the proverbial straw that broke the back. The only ways I can see a front diff failing: 1) slowly damage it, then it fails catastrophically at some tipping point; 2) something works loose inside it; 3) manufacturing defect.

Hopefully we'll know more when we inspect the parts. Thanks for the tip on the bushing. I'll look into that next time I pull the skid plate, and will ask the dealer to verify as well when he's done rebuilding.

Thanks!

 

[lugantom]

UNH! Still waiting on the ring gear, and another snow storm on the way! At least the loaner car gets better mileage.

So, while I wait, I've been doing some research on options for my drivetrain. Gave a call to Randy's Ring & Pinion, as I've always heard good things about his shop. Randy's advice was that the GM 7.6 IFS is fine for my application (not hard core rock crawling, no bigger than the factory 33s). He said that the 7.6 IFS has a good reputation, and that I was probably unlucky to have the failure that I did. He said the constraints of its size make it difficult for aftermarket manufacturers to offer much in the way of upgrades for it. So, I'm satisfied that, once my front diff is back in action, I should be able to keep it.

So, my list of possible upgrades now includes:
1) The upgraded differential support bushing I've heard about here on the forum
2) RCV's upgraded CV joints

Questions:
1) Anyone had any experience with the RCV CVs? At $325 a pop, not super cheap, but probably well worth it if I can avoid a field swap of half-shafts.
2) Anyone know of an upgrade for the CV joint on the front propeller shaft?

Again, THANKS for the help! Love my truck, looking for ways to gain confidence in its front drivetrain!

 

[Best4x4]

I think your better off with the stock or new aftermarket CV's vs the RCV's. At least you'll break a 100.00 set of CV's vs a $$$$ Front Diff. I come from Jeep's and almost all my friends upgraded their Dana 30's with cromoly shafts, which yep they didn't break, but the damage went further up like the ring/pinion gears, or worse case the transfer case. All my Jeep buddies gave me heck for buying the H3 saying I'll snap a CV just hopping a curb, but I'd rather change them out vs more $$$$ parts, and 100.00 max for a pair of new front CV's for my H3's is about 300.00 less than the axle shafts on a Jeep!

The bushing is what I'd call a GM/Hummer boo boo. It's just designed to fail in my opinion. You've got the hot engine/exhaust near it, and once she lets go your front diff is free to move up/down anytime it wants causing wear on the upper diff bushings, CV's, and drive shaft/CV. I was going to get the OD kit and rebuild mine, but they weren't available so I went with the Scorpworks replacement with the new bushing. It was a quick and easy purchase. I ordered it, payed the core charge, received it, installed it (in under 30min), and sent my original off for the core charge which I got back very quickly. My diff no longer bounces up/down and if it ever fails they'll replace it.

My first vehicle I ever owned was an 87 Mitsubishi Montero 2Dr and I wheeled that thing all over the place (more than any of my Jeeps) and I only got stuck a few times. The IFS clunked, and you could feel it flexing/moving in a parking lot, but it never failed me. I think the H3 setup is fine as long as all the components are in good working condition like the upper/lower ball joints, CV's, bushings, and diff bushings.

I haven't had the time to install my new upper/lower ball joints, and CV's, but I'm pretty sure it'll take care of the added stress the previous owner put on it by going into the 24 1/2 range on the torsion bars. When I first got it I could barely park it into a parking space without the front CV's binding!!! I'm almost certain that plus the 109K on it didn't help the uppers or the CV's. The lower ball joints look fine, and so do the CV's but I am going to do it all at once and get it over with.

I did the tune up on our new 07 Hummer H3 Adventure Saturday. Had a few things fix that the dealership didn't do properly like drain some fluid from the brake reservoir (was pouring out all over the place upon bringing it home), and fixing the brake guide pins that one clip had already fallen out causing the pin to almost jam between the rim. And last but not least was an oil change since they didn't touch it.... They did replace the windshield, Yaw Sensor, brake pads, but forgot a simple oil change. It had the wrong filter on it (half the size of the correct on) and the oil wasn't very good looking. I cleaned the throttle body, replaced the air filter, fan clutch, and spark plugs. It runs much better and doesn't hesitate like it did when you stopped and then tried to take off.

 

[Mr_Rich]

I'll speak about the oil disappearance issue. I won't call it oil burning because I don't think that's the case. On the LS1's in the earlier F-Bodies the oil was sucked into the intake through the PCV system. Some of the guys install a catch can before it goes in to the intake. I installed an LS6 engine which has a redesigned PCV system in my Firebird and that took care of the 1 qt. per 500 mile problem. There was no evidence of gummy plugs or oil burning in my LS1. The oil simply pooled in the bottom of the intake and got sucked through the engine.

 

[Best4x4]

I agree it's not burning oil in the usual manor.

 

[alrock]

Questions:
2) Anyone know of an upgrade for the CV joint on the front propeller shaft?

I've yet to witness a prop shaft CV joint failure on the trail; not that many on the street either. I carry a spare but I don't see a reason to upgrade it. They don't snap like twigs like in some other vehicle's drivelines.

 

[Zach]

I've yet to witness a prop shaft CV joint failure on the trail; not that many on the street either. I carry a spare but I don't see a reason to upgrade it. They don't snap like twigs like in some other vehicle's drivelines.

Have seen a few on mall crawlers

 

[lugantom]

Thanks again to all for the help. Still don't have my truck back, just drove my loaner car through another snow storm with another headed this way this weekend. Miss my Hummer (although it is a pretty nice loaner car).

Pretty frustrated with GM. Every axle shop I know has the 4.10 ring and pinion set in stock for the 7.6 IFS front diff used in the H3. But GM says that they don't have a single set available in any parts warehouse or US dealership, so they say that I'll have to wait until the manufacturer produces one and ships it to the dealership. They won't give a time frame. I'm guessing anywhere from days to weeks.

I won't bother listing how completely uncooperative and unhelpful the GM Customer Service people are. My dealership has been great, but it seems that their hands are tied since it's a warranty repair. Kind of shocked at how bad GM is.

I suppose I should just be thankful that I have a really nice loaner car, and do my best not to get into an accident trying to drive a FWD sedan in the deep snow ...

 

[lugantom]

Well, hope does spring eternal! Jeff Perry, my local dealer, has patiently endured my friendly suggestions and repeated phone calls. Schepel in NW Indiana, who sold me my Hummer, also came through for me. It's not a done deal yet, but it's looking like we have located the last OEM ring and pinion axle set (bearings, etc.) for an H3 Alpha in North America if not the world. Should have it Tuesday, and are guardedly optimistic that it's the right part and will work.

For those who may one day wonder - there are plenty of aftermarket options for the 7.6 IFS. I was a bit confused, because I thought Randy's Ring & Pinion had told me otherwise, but I have confirmed that Yukon Gear and G2 Axle & Gear do offer the equivalent of the GM kit for the 7.6 IFS axle.

For those who may still have warranty coverage - try to not break your front differential. If you do, you won't be able to get the parts. Anywhere. Ever. That may be a slight exaggeration, but virtually nobody could track these down. Here's what I learned:
Most every parts search will give part 20801812 for the "gear kit". Upon inspection, it will list the 3.7 L I5 as the application, not the 5.3 L V8, but it will tell you that 20801812 is OK for the 5.3 L V8 when you confirm against your VIN. Doesn't really matter, because 20801812 is discontinued. There is one part left at a dealership, I think in Michigan, and he won't sell it. So, if you need a warranty repair, you'll have the same problem I've been having. They'll agree that they are responsible for the repair, but they won't be able to do it.
After working with both dealerships, we concluded that the correct part for the Alpha (5.3 L) is 25801719. I think I got the last one on earth. We aren't 100% certain that it's the right part, because the linked parts breakdown suggests that it doesn't have a ring gear. We all agreed that, based on price of the part and common sense, the ring gear MUST be in there. We'll find out Tuesday when the part arrives.
Why is this important? Because, as far as I can tell, it would take an Act of Congress for GM to authorize use of aftermarket parts on a warranty repair.

I'll post what happens on Tuesday. Here's hoping I'll have my H3 back on the street next week! Unfortunately, that's probably right around the time when I won't need to worry about the snowstorms. :->

 

[JoeFireGuy]

CRAP!
I just posted a similar problem with my '06! I may be up the creek if no parts are available....
Joe

 

[alrock]

lugantom, parts like this have been a somewhat common issue with the H3. GM's supply dwindles to zero before a new batch is delivered from the part manufacturer. I had to go through the same issue a few years ago with the power steering pump. The one I got came off of a manufacturer test vehicle that member Brodie was getting parts from. It was going to be weeks to get a new one.

Unfortunately, the supply levels seem to ebb and flow. Sucks that you got caught up in one of the low supplies but I'm glad to hear that you'll be fixed up soon.

 

[Steve #1]

I waited over a month to get a transfer case. Granted, it was during the 2010 shutdown when they were deciding what to do with HUMMER.

 

[4speedfunk]

He said that the 7.6 IFS has a good reputation, and that I was probably unlucky to have the failure that I did.

...downright laughable. Its amazing what people will believe.

 

[lugantom]

A l m o s t t h e r e ...

Turns out the revised part number was the correct one, and dealer now has the full gear kit. Patient is in surgery, and hopefully I'll be back in the H3 before tomorrow's snowstorm hits. I will miss the bluetooth on the loaner car, though ... My 2008 Alpha has the premium touch screen, etc., but didn't have bluetooth yet.

I'll let you know if my truck lives tomorrow!

4speedfunk - short of a solid axle conversion, what would you do to beef up the 7.6 IFS? Do you think an aftermarket gear set would be stronger?

Thanks!

 

[4speedfunk]

Nope... It is what it is. I think the best thing you can do to the AAM-7 is to beef the mounting points as much as possible. There are three bushings the hold it in place and I personally feel these have a lot to do with failures. Several companies make both crossmember and outboard bushings that are much stiffer and keep the housing from pulling itself apart.

Cryogenic treating and/or aftermarket gears probably won't do much because that's not the problem. Housing flex is the real issue. The stock bushings allow the whole thing to flop around way too much.


Sent from my iPhone using Tapatalk

 

[MaxPF]

...downright laughable. Its amazing what people will believe.

At least they have a sense of humor about it, right? Perhaps the 7.6 is fine if tires are kept at stock size and the vehicle never goes off road. Ever.

 

[4speedfunk]

Perhaps the 7.6 is fine if tires are kept at stock size and the vehicle never goes off road. Ever.

Possibly. After-all, Yotas and Dana 30s seem to take comparatively much more abuse, and they are a similar size.

I've always thought that if you could rigidly clamp an AAM-7.6 to a test fixture...ramp up the input torque...put a load brake on it...and push it to the point of failure...you might be surprised how much that little turd can take. I think the failure rate has a lot to do with how its mounted to the truck. The crappy mounting system essentially "de-rates" it from its true potential. Its just a theory. There has never been an axle more in need of a truss than the AAM-7, and I've got one designed. I just didn't pursue it due to the limited gearing options. Even if you could beef it up...you're stuck with 4.56s and that pretty much seals the deal for me.

 

[MaxPF]

Possibly. After-all, Yotas and Dana 30s seem to take comparatively much more abuse, and they are a similar size.

Toy axles are a bit bigger (8" approximately), and both they and D30s are under vehicles that weigh significantly less than the H3. I'm also guessing both are more rigid and heavier than the AAM 7.6 case. The D30 has to support axle tubes, while the Toy axle is a third member bolted to a fairly rigid steel housing. There are other factors as well: bearing sizes? Bearing separation distance? Carrier rigidity? Gear design? Pinion offset?

At a minimum the H3 should have been equipped with the 8.25" IFS front unit used in 1/2 ton pickups. The engineer (or, more likely, the bean counter) that decided the 7.6" was big enough needs to be kicked in the balls.

 

[lugantom]

Appreciate the insights. I was spoiled - I had an '83 Ramcharger and an '06 Wrangler. The '83 Ramcharger, believe it or not, had a Dana 44 FBJ - full float. People never believe me when I tell them that, but, yet, that truck came with a full float front axle. Was also before the center axle disconnect (CAD) system. So, I was pretty shocked to have a front diff fail on a truck that I very rarely take off-road.

Still waiting on my truck, but I'm OK with it. The dealer said they want to change 2 more bearings, and had to wait on one of them. They did inspect the diff mount bushings and said that they are OK and were not the cause of this failure. Should have the truck back tomorrow or Monday. The guys at the dealer understand that I'm less worried about the time it takes than the thoroughness and quality of the job. I've had enough surprises with this drivetrain!

Thought hard about trading it in, since a low miles loaded '08 Alpha is probably still worth a bit, but I really do love the H3's design. Think I'm in it for the long-haul. My R/C was already an orphan when I bought it in about 1996, so I'm used to the sacrifices it takes to keep a discontinued vehicle on the trails. That old R/C has over 400,000 miles and still runs great. I gave it to my nephew when the body got too rusty.

Anybody know of anyone who swapped GMs larger IFS axle into an H3? I wonder if that's possible ...