Ok, I know I like to go off roading but I found this out after I bought my H3 without the Adventure package. When I upgrade in '08 I will for sure have the adventure package.

The dealer called me this morning after having my car for a week and said they finally found the noise I was complaining about. They opened the front Differential and every other gear is either cracked or broken! Whoops!

It has become very clear to me that you need a rear locker in the H3 for any sever off roading otherwise the stress to the front diff is too much and the gears break. At least this is my take. I off road with other H3's and they don't have any problems with theirs since they have the rear locker.

Anyone else want to share some thoughts on this??

Mike

 

i doubt it's all because of the lack of a rear locker. i know an H3 owner that destroyed the front diff in Moab, and it has the adventure package. same symptoms, gears cracked. could be a bad bin of gears on the assembly line. the front is still going to try to pull just as hard whether you have a rear locker or not, it would just have an easier time with the rear pushing a bit more. once your traction control kicks in, that stress could be what ate the gears. good job though, croaking the front diff. congrats.

 

I agree, if it's going to happen, it doesn't matter what package you have. I don't think the rear locker is going to change anything. A front locker would only add to the carnage. I've heard of many people toasting the front diff. What exactly is it that breaking? The ring gear? I just hear the usual "busted front diff" without much explanation. I'd like to know if what exactly keeps failing in there.

I do know that if gears are not properly broken in, (at least 500 miles of driving) they can be easly damaged when strained. Perhaps GM didn't implement any type of break in period for the front gears? When the gears are run, they get hot, and sort of stew in the diff oil. While they are warm, the oil tempers the gears metal, and makes it harder. New gears, without a correct break in, will be too soft, and will shear, crack, deform, and just plain break under high stress situations. (this is one of the reasons you're told not to tow, avoid hard starts ect durring your vehicles break in period. It's so that the rear diff can get broken in, before it's needed for anything stressful to it.

But, I have no idea what's getting broke in the H3's front axles, so I'm not sure if this is whats going on. It sounds like I may be running my 4wd for a mile or two here and there to temper the front gears, so I hopefully won't have to worry about it. Perhaps then when the wheeling gets tough, I won't pop the front diff. Without knowing what the problem is, it's about the only preventative thing I can do.

 

you're already running in 4wd, all the time. just put it in 4lo and drive through the neighbors front yard for a while.

it would be nice if the dealership would take some pics, so we could all see the carnage. then those that want to know what is breaking can see, and those of us that just like mechanical carnage can enjoy . . . . .

 

I know, but is it getting enough load to heat up, so that it can temper? I thought about the fulltime aspect too.. but I just don't know if there is enough load, or heat to truely break in the gears. Maybe there is, I just don't know enough about what's going on in there durring normal driving to say for sure.

It's also hard to know what to do to prevent the failure, when you don't even know what the failure is exactly. If it's the ring and pinion, they could be a faulty batch, not broke in.. or weak from the start. If something on the carrier is breaking, then there really won't be a fix since it will be a weakness issue.

Oh well, maybe it will last me until the warranty is out, and I can swap in a solid front axle.

 

The dealer is going to take some pictures for me tomorrow when they swap it out. I'll post asap.

I have to say, the dealer is awesome. This is the second time is has happened and they told me not to worry about it. He said if they(Hummer) didn't want me to off road with it then they shouldn't have marketed it as an off road vehicle.

 

Why are the front diffs exploding? Is this also a problem in the Canyons and Colorados? It just seems odd that they are failing so easily. As a former Jeep guy, I had the weak Dana 35 rear end in my Wrangler. But, even after adding a Detroit Locker and 35" tires it had NO problems for over 75,000 miles and very serious off-roading. Are these front diffs breaking because of driving style. I always would finesse my vehicle while off-roading to avoid breaking parts. Are people just jumping on the gas and driving too aggressively? This all just strikes me as very odd.

 

The speculation right now is that the front diff is flexing under maxiumum restriction (i.e. boulder, tree under water, etc.) because it is aluminum, the pinion gear rides up on the ring and starts to chip teeth.

GM has released some hardened ring/pinion gears but that is what the dealer is replacing now.

As far as my style of off roading. I drive very slow and take my time through a course or trail. No speeding at all. I use BTM to get through the tough moguls, etc. and thats when you get the flexing.

 

What does BTM mean?

 

Brake Throttle Modulation

one foot on the gas, the other on the brake. keeps you from flying up an obstacle and crashing down on the other side. also keeps the traction control off. takes a bit to get used to, but works great climbing rock ledges and boulders.