Rear/front diff

[PARAGON]

1) What was the whine/noise thing a while back about the rear diff where they replaced it.

2) Anyone else spun out or broke either their front or rear diffs/ring/pinion/spider gears?

3) Which ring/pinion is in both the front and rear.... tooth count on the ring gear, etc?

[f5fstop]

Originally posted by PARAGON:
1) What was the whine/noise thing a while back about the rear diff where they replaced it. Lapping compound left on the gears by the manufacturer (American Gear/Axle). Needless to say, over a period of time, it lapped the gears a bit too much . Does not affect vehicles built after August 10, 2005.

2) Anyone else spun out or broke either their front or rear diffs/ring/pinion/spider gears?
Top warranty hits show no front axles replaced, some rear axles, but that should be explanable by the previous issue (lapping compound). This does not mean there were no axles replaced for other reasons, but the number was too small to appear in a top 200 warranty issue report, and puts the instances per thousand vehicles at a very low number.

3) Which ring/pinion is in both the front and rear.... tooth count on the ring gear, etc?Can't help right now, system is down. But from my old memory, I believe front axle is 7.5, rear axle is 8.6. Not sure if I have teeth count anywhere, but when the GM system gets up and running again, I'll check.

[Sewie]

I had my front diff replaced a few months back. It didn't completely shatter like Neo's or Bebe's but the tech told me there were some chipped teeth. I was gone while they were working on it so I couldn't check out the damage.

I still don't know exactly how it happened. I didn't even notice it until driving on the highway. Even then I was able to drive it for about a week before taking it in to the dealership.

[f5fstop]

Did you have trouble with one of the axles?

This the the best information I could obtain today.
Rear axle is either a AAM 800 or 860
AAM 800 - 205mm (8.07 inch) ring gear diameter with a TracRite EL rear differential. (If it is this axle, I stand corrected in my original post.)
AAM 860 - 220mm (8.66 inch) ring gear diam, with a TracRite EL differential.
Either one is cast iron.
Front axle
AAM 725 185 mm (7.28 inch) ring gear TracRite (think it is the GL series) with an aluminum casing.

[PARAGON]

Neo and Bebe's situation is very curious and makes me wonder if the slowness of GM to offer more power is associated with something along these lines or not.

There's one picture where it's obvious the pinion spun some teeth off the ring gear. It seems the same occured in all three instances on both trucks and that maybe even the I-5 is offering too much torque for this diff setup and the weight of the H3.

I would suspect if you tied 10 H3s to anchors and slowly applied the torque on a surface with good traction, several of them would spin out the ring gears if there was some weight transfer. This without the usual culprits of bouncing, over-spinning, etc that is usually associated with this kind of breakage.

[MarineHawk]

Would a 2.56:1 transfer case consequently be better than the 4.00:1 one - delivers less torque in 4W-Lo?

[f5fstop]

All I can say is that the 3.7L will have the same axles; however, when the 5.3L comes on board, it will have a larger front axle for sure; not positive about the rear axle (but I did hear rumors about the next size up).
The overspinning when going over obstacles should be taken care of by the traction control system that limits the spin of the wheel in the air. Preventing the the well know axle grap...axle break or diff problems.

I really haven't heard of any problems with any of the axles other than the lapping compound problem. (I should say other than leaking drive shaft axle seals, caused by incorrect install of the axle. Hopefully, this was fixed by waking the guys up on the line and having them use the seal protector tool versus eyeing it. Easy fix at a dealer.)
I know the GM test guys did some hard testing on the vehicle prior to, and after vehicle launch.

The reason the I-5 was used was because at the time, it was the only engine available to fit in the compartment. The I-6 was too long, and production of the 5.3L was not up to the numbers they needed (and modifications were required to fit it in the engine compartment). The 3.5L was the logical engine to use, and GM has been blasted for the underpower of the engine by every magazine.
They had the 3.7L on the books prior to launch, but it takes a while to test, test and test. In a few months, the 3.5L will go out of production, and the 3.7L will take over.

I know the brand quality guy for this engine get reports everyday on any component that hits a certain number of replacements or rebuilds. This information comes from the dealers via the labor operation number for the part replaced.
This number is set pretty low, that is why with only 100+ cylinder heads replaced (out of over 100K engines on the road), the brand quality guy was all over the problem, working with engineering. Once the problem was found, the cylinder heads were stopped, which caused a shortage, and new ones with hardened valve guides were produced.

If I see a spike in the numbers (I get the labor operation number run once a month), I'll speak up.

I sure hope there is no problem, and this is just a fluke, but unless there VIN numbers are close, I can't see it as a quality spill from AAM.

Didn't know Neo and Bebe broke the front axles. Do you have photos. I would love to send them to the axle guru at GM and see what his reply is. I would be curious to see if he tries to pound sand up my rear or give me a straight answer.

[PARAGON]

I'm thinking, just thinking mind you, that everything was being lined up and there was no combination GM could put together that would offer a sufficient power plant off the bat that would match well with what could be produced throughout the drive train.

Maybe they needed to go with tried and true, as I'm sure something could have been done to accomodate a different engine in the design phase. It's a moot point anyway, just a thought.

I'm just wondering if the torque is too much for the diffs. Just odd to spin teeth off of 2 different ring gears, two different rigs, same day, etc.

There was a picture posted somewhere on here by someone from Moab and I think it was of Neo's diff. Maybe someone else remembers where it was.

[evldave]

http://elcova.com/groupee/forums/a/t...771084871/p/26

about halfway down. note: from the discussions (I wasn't there) this happened at the same place on the trail for both rigs.

[PARAGON]

interesting

it uses AAM calls their PowerDense ring/pinion set. Supposedly to offer more torque control in a lighter package.

Well, I get wary anytime a company has to call something a "special" name for something to do what it's supposed to do.

[PARAGON]

<H1 align=center>Technology Update: Differentials Provide Customers with
Improved Traction and Handling and Reduced NVH</H1>


DETROIT, March 3 -- The <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=American%20Axle">American
Axle</A> & Manufacturing
(AAM) TracRite(R)
differentials for both front and rear axle applications have been designed to meet a
variety of customer requirements for traction control and improved ride and
handling. The AAM family of differentials range from its current
industry-standard mechanical differentials, to its newest, most sophisticated
electronic traction-enhancing architectures. When coupled with the SmartBar(TM)
roll-control module, AAM's TracRite
differentials provide maximum traction and handling performance with reduced
noise, vibration, and harshness (NVH).</P>


TracRite differentials feature PowerDense(TM)
gear sets and net-shaped forged and piloted side gears for low lash and quiet
operation. Two of AAM's newest TracRite
differentials are the <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=TracRite%20EL">TracRite
EL</A> and <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=TracRite%20GTL">TracRite
GTL</A>.</P>


AAM's advanced <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=TracRite%20EL">TracRite
EL</A> features lightning fast (50 milliseconds) engagement and disengagement
and is lightweight and compact. It offers scalable high-torque capacity, low
electrical power and actuation that can be programmable, driver selectable, or
both, and is compatible with ABS braking.</P>


The <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=TracRite%20GTL">TracRite
GTL</A> is a helical gear differential with a locking feature. The locked mode
may be engaged automatically via a programmed computer, driver selection, or
both. The GTL continuously biases torque to the higher traction wheel to prevent wheel
slip, and features a tunable torque bias ratio.</P>


"We have engineered and designed a family of differentials to meet and exceed
our customers' expectations and needs," says <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=Daniel%20V">Daniel
V</A>. Sagady, P.E., vice president, Engineering
& <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=Product%20Development">Product
Development</A>. "Our line
of AAM differentials builds important performance advantages into our customers'
vehicles. For instance, an SUV equipped with a TracRite
differential in both the front and rear axle can provide true four-wheel drive. In some four-
wheel-drive applications, the transfer case can be greatly simplified, providing
significant advantages in packaging and mass reduction, while creating full-time
all-wheel drive."</P>


AAM is a world leader in the manufacture, engineering, design and validation
of driveline systems and related components and modules, chassis systems and
forged products for trucks, sport utility vehicles and passenger cars. In
addition to its 14 locations in the <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=United%20States">United
States</A> (in Michigan,
<A class=tspt
href="http://www.theautochannel.com/search/search.html?words=New%20York">New
York</A> and Ohio),
AAM also has offices and facilities in Brazil,
England,
Germany,
Japan,
Mexico
and Scotland.</P>


Certain statements contained in this press release which are not historical
facts contain forward-looking information with respect to the Company's
plans, projections or future performance, the occurrence of which involves risk
and uncertainties that could cause the company's actual results or plans to
differ materially from those expected by the company which include risk factors
described in the Company's
filings with the Securities
and <A class=tspt
href="http://www.theautochannel.com/search/search.html?words=Exchange%20Commission">Exchange
Commission</A>.</P>

[f5fstop]

Design phase started with the Colorado/Canyon. Unquestionably, it was less expensive for GM to design the vehicle around the same engine as the optional C/C engine, and then set up for a new set of axles, and diffs, etc.
Might not have been the correct thing to do, and I have to admit, looking at that destroyed differential, does not give me a warm and fuzzy feeling.

[HummBebe]

Does not affect vehicles built after August 10, 2005.

I purchased my truck on 6/30/05. But I think you already checked my VIN.

[f5fstop]

Originally posted by HummBebe:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Does not affect vehicles built after August 10, 2005.

I purchased my truck on 6/30/05. But I think you already checked my VIN. </div></BLOCKQUOTE>

Not sure. But that only affects rear diffs, and if you have any substantial miles on the vehicle, you would know if that problem exists. The wear caused by the lapping compound made the axle very noisy. But, while your vehicle is in service, ask the dealer if they would pull of the rear cover and check for debris.

[Bully13]

Here's the pic from the other page. I hope that it's ok that I post this. I just thought it would be nice to have this photo on this page.

[NEOCON1]

that is bebe's front diff . i think mine probably looks about the same but mine is in salt lake . so we havent seen what it looks like with the diff covers pulled .


still in moab drinkin beers

[Mr. I - Man]

It looks like a metalurgical problem the teeth don't look stripped or sheared off in the case of a high torque load, it looks more like they cracked off due to porosity (bad alloy mixture,bad casting or bad block of raw material if they are a machined and forged parts )

[Bully13]

Is this covered under wnty? Sorry if this was asked already.

[f5fstop]

Better be covered under warranty.

[Sewie]

Mine was replaced under warranty.