Hi everybody,
I'm just confused from my front diff. Without any offroading or hard impacts my diff starts to vibrate in slow acceleration. In hard acceleration it is ok and same without any gas. So I open the cover and suprise - black oil with iron splinters I guess it is not good. So I check all the gears and found two claws are 20% cutted, also in differential cage I found the inner gear also two claws 20% cutted. Changed oil, clean all surfaces, check..but nothing?! After 200miles with clean oil etc. again grey..something is wrong?! Still vibrating but with cold/freezy oil nothing.

Can anybody help?
Also do you know, where can I buy new diff with locker for 2007H3?
Thank you all for any info.
Peter

 

Chipped teeth, What weight oil did you put in there?

 

SAE80 local manufacturer

 

Theres your problem.

Front and Rear Axle
SAE 75W-90 Synthetic Axle Lubricant (GM Part No. U.S. 89021677, in Canada 89021678) meeting GM Specification 9986115.

 

tHIS IS A KNOWN ISSUE WITH THE h3 AND IT'S NOT A GEAR LUBE PROBLEM. tHER HAVE BEEN ALOT OF THESE FAILURES AND gM KNOWS IT'S A PROBLEM AND THAT IS WHY THE aLPHAS AND THE 09+ADVENTURE PACKAGES HAVE CAST IRON DIFFS IN THEM. imo THEY SHOULD HAVE PUT A BIGGER DIFF AND CAST IRON FROM THE BEGINNING. aNYWAY IF YOU HAVE WARRANTY LEFT THEY SHOULD COVER IT OTHERWISE THERE ARE A FEW OF THE DIFFS OUT THERE FOR SALE. i'M RUNNING A d44 CENTER SECTION IN MINE WHICH IS A LOT TOUGHER, AND HAS GEARING/LOCKER OPTIONS THAT THE STOCK h3 DIFF DOES NOT HAVE. i'D BUILD SOMEBODY ONE IF THEY WANTED (IT CAN BE HAD BUT IT AINT CHEAP)

 

Thank you 4DIGR, hard to find some better diff with same ratio. Or Ihave to change both diffs to maintaine same gear ratio..
do you know some shop where I can buy better (like OEM) diff?
THX

 

The only better like OEM diff that you will find is the cast iron version from an H3 alpha or a 2009 or newer H3 with the adventure package. If you can find an 09 or newer adventure package front diff that came from an H3 with the I5 engine in would have the correct matching gear ratio (4.56for I5 engine) already in it and would be a bolt in unit. If you found one from an alpha it would have 4.11 gears in it and would require you to change gears to work. That is a doable option although it would cost a fair amount more to go that route. Except for the gear change the diff would still be a bolt in otherwise.

In no case should you have to change both diffs to maintain the same gear ratio. The D44 that I have in mine I custom made and It has gear ratio options for it that match the available rear H3 ratios down to 5.38. I would sell one of these D44 upgrades if someone was interested but the cost uninstalled is about $2500.00.

I'll do some checking on who might have a cast iron H3 diff and get back to you.

 

GMpartsdirect, part #25892846 is supposed to be the cast iron front diff, 4.56 gears, with locker. Any gm dealer should be able to verify what that part number is, I don't know for an absolute certainty that it is the part described but the number came from a good source (dealer parts guy). gmpartsdirect lists the assembly for $1399.93 +freight and I don't know about availability.

Also you might do some searching at the HummerXclub, The Broken over there had one from an alpha for sale awhile back, and I think that someone at clubhummeroffroad had one also.

If you've got an 07 with under 100K on it they should warranty that for you.

 

Thank you.
In our club where we have approx 60 H3s we have 12 Alphas and 3 of them have a failure of front diff. As I saw what is inside, I do not think it is better then mine. From the old H3s only 2 from 50 have some failure.
As I going trough the problem with me is that I have a big tires (35'') and the side bearings went out so the movement of inner gears was too big and then some claws gone..
Finally I decided to change ring and pinion, gear set and bearings. Hope that it will be ok for another 50k miles..
Tomorrow I will work on it so I will let you know
Petr

 

The internals of both diffs are the same, what makes the alpha better is the cast iron case that the front diff case is made of,vs the aluminum that the base has. There has been alot of discussion on exactly what is at the root of the failures, case flex/deflection under load is suspect in the aluminum ones, and people have literally blown the gears out the side of the case on them. There is also the belief (that I agree with) that even with the cast iron version, the ring and pinion are just not strong enough for the torque that is being put to them. The front diff in the cast iron version is substantially smaller and weaker than the rear diff in the H3. That is why I put the front diff that I did in mine as it is roughly equivalent to what is in the rear of the H3 and about 30% stronger than the cast iron front that they put in the H3. For more info check this out.http://www.hummerxclub.com/forum/sea...aser&start=135