2008 Hummer H3 Alpha

[JPaul]

Unfortunately there was also damage to the ring gear and tiny nick to the pinion from what I can see.

Looks like a chunk was wedged between the nose of the pinion and the carrier:

A small flake is all I saw on the pinion:

So now I'm trying to determine what exactly to do. I was going to buy a used axle off Ebay and just swap it out, but the seller was being adamant about not doing a warranty since the RPO codes didn't match exactly (only difference was one had a locker, the other didn't) so I backed out of it. I theoretically could just get new spider/axle gears and run it for a while, but I'm not sure if the bearings got eaten at all from the debris, though I didn't drive it very far at all until I cleaned it out, maybe a couple hundred feet, and at only a few MPH.

Otherwise I am going to just pull the front and rear axles and take them to a shop to have them rebuilt with 4.56 gears instead of the 4.10 gears, and probably go with ARB air lockers. I really don't like the way the Eaton E-Locker functions, there is a fair bit of slack that needs to be taken up to fully lock them, and then if you need to roll backwards at all they unlock and then relock, so it's a trick to make sure that you're not in a situation that can cause the locker to slam lock which just breaks stuff. With the ARB you still have some rotation to lock it, but it is a fraction of what the Eaton needs, and once it's locked it stays locked until you unlock it regardless of forward or backward motion. Obviously it's the much more expensive solution, but it's also the stronger and more reliable solution in my opinion.

I spoke with a shop yesterday that was recommended to me and they should be calling me back today with a quote. I talked to another shop and labor for front and rear was going to be approximately $1400, so I'm figuring redoing everything is going to end up running around $4500 or so if I go with front and rear ARB lockers. If I am going to do it I should do it all and do it right. It's still cheaper than a ZR2.

 

[JPaul]

Video of the diff:

[VIDEO]

 

[JPaul]

More pictures of the damage. I pulled the axle assembly completely out in preparation for taking it to the shop that will be rebuilding it for me, and tore it the rest of the way down but left the carrier installed in case they wanted to check everything, plus I know you need to keep the caps with their respective sides and orientation.

Back of driver gear. Starting to see the slots rounding off.

Locking pins. All starting to round off a fair bit from the looks of it.

Closer look at the front and back of the passenger gear:

Passenger axle bearing surface and splines:

Driver axle bearing surface and splines:

No apparent damage to the axles themselves and the bearing surfaces seem fine. The passenger axle splines look a bit excessively peened though, so I'm not sure if I am going to want to replace them anyway.

It's just as well that I am having the diff rebuilt, after getting everything pulled out and flushing it some more with brake cleaner I tried rotating the ring/pinion gear, and some little bit has apparently worked its way into either the carrier bearings or the pinion bearings and now it binds really badly. I can only turn the carrier maybe 20 to 30 degrees in either direction before it binds up. But I talked to the shop again and rebuilding the diff with an ARB, 4.56 Nitro gears, and new bearings and whatnot is only going to run around $1800 or so all together. The front will be similar so I'm pretty pleased, especially since I was figuring it would run towards $5k for both axles. They said they should have no problem getting the rear axle done before my trip down to Overland Expo West in May, so I should be OK. Just need to get the axle over to them and find out when the locker is going to come in, sounds like it might not be until the end of next week, but that should be OK.

 

[JPaul]

Dropped the axle and ARB locker off at the shop, hopefully they can get it done this weekend and I can pick it back up on Monday. I'm going to pull the front axle this weekend and get that all prepped as well. The front ARB locker is taking longer to get to me but that's OK. It'll be great to get this thing back on the road soon, and I'm looking forward to seeing how it performs with the 4.56 gears.

 

[digitalnomad]

It looks like that failure was severe. It is as if more torque was put to the diff than it was designed to handle. Any ideas on why it failed like that?

 

[JPaul]

It looks like that failure was severe. It is as if more torque was put to the diff than it was designed to handle. Any ideas on why it failed like that?

I think the same thing, that driver gear appears to be what gave out first. You can see that the missing teeth are 180 degrees from each other, so I think what happened was the driver axle gear gave out first due to the sheer amount of torque on it (5.3L V8 with a 4:1 transfer case and the transmission in first gear in a rig that at the time probably weighed in around 5200 pounds, maybe more), then the shock weakened the one spider gear and maybe cracked the passenger axle gear, then when I drove it further up the trail it cracked the spider gear in half and that punched a hole in diff cover.

The Eaton does fine for the most part in these rigs, especially when it's just the 3.7L I5 engine and the 2.64:1 transfer case. But my rig is a bit more powerful, so it was probably just too much with only 2 spider gears and how thing the driver gear's backside is. The ARB I'm putting in has a much thicker driver axle gear (it's still the driver gear that gets locked in place) plus it has 3 spider gears (they didn't do 4 due to needing to be able to put the c-clips on the axles but it should be fine for my needs). It should fare a lot better and I'm hoping it will last the life of the vehicle aside from minor things like new orings and such.



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[JPaul]

I may end up replacing the axle with a Dana 60 or GM 14 bolt later on, the 8.5 is fine but possibly a bit undersized when paired with the V8, especially when running larger tires and running tought trails with it. I'm only running 33's though so it will probably be fine with the upgrade to the ARB locker. I might go to 35's, but I don't really see a need for it, plus it would affect my towing ability, even with the 4.56 gears.

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[JPaul]

Talked to the shop today, rear axle should be ready tomorrow so I'm borrowing my friend's truck again to pick it up. Hopefully I can have it installed tomorrow night and be back on the road again. I spent last night and tonight pulling the front differential and CV axles. Turned out to be a good thing I'm doing it.

Here's that CV that had the boot popped loose:

And then when I was pulling the front drive shaft I started to undo the bolts at the transfer case, pulled my ratchet out and noticed it had grease on it. At first I thought I somehow got grease on it from working on the axle above, so I wiped it off and went back to loosening the rest of the bolts for the driveshaft at the transfer case. Pulled the ratchet back out and there was MORE grease!! Crap.

Turned out to be a nice little line of grease from the CV for the front drive shaft on the crossmember:

Turns out the clamp for the boot somehow got crushed by a rock or something (guessing it pinched a rock between the clamp and the outer portion of the CV) and now it's just loose enough that grease is starting to come out. Brilliant.

It's the original driveshaft from the looks of it, so it's probably just as well that I have to replace it now. The question now is what do I do? I have a few options.

1. Replace the CV with a Cardone unit
2. Replace with a used or new stock driveshaft
3. Upgrade to a aftermarket driveshaft (Tom Woods has one, bit pricey though but supposedly nice and uses a double cardan with Spicer 1310 joints, Outfitter Design has one that costs even more than Tom Woods but is simpler as it doesn't use a double cardan joint.)

Fortunately this issue can wait for a bit, it's probably going to be a while before the front diff s rebuilt. But it's just another issue that has come up. I am really surprised to find so many things broken/breaking after this last Moab trip, I didn't think I was anywhere near this hard on the rig. But when I am done it's going to be practically a brand new truck from the frame down.

 

[BPD53]

1. Replace the CV with a Cardone unit
2. Replace with a used or new stock driveshaft
3. Upgrade to a aftermarket driveshaft (Tom Woods has one, bit pricey though but supposedly nice and uses a double cardan with Spicer 1310 joints, Outfitter Design has one that costs even more than Tom Woods but is simpler as it doesn't use a double cardan joint.)

The stock front driveshafts are known to sling grease and are definitely a weak link so I'd upgrade for sure. I have no experience with the Outfitter Design shaft.

I'm running a Tom Woods front shaft and it's been great so far. It's literally a night and day difference when comparing it to the stock front shaft.

 

[JPaul]

Got the axle back today. Unfortunately it took me all evening to replace the u-joints on the rear drive shaft. It didn't help that you need a special tool to press the old u-joints out, which I had to fabricate:

But the driveshaft is ready now, so hopefully tomorrow evening I can get the axle installed and take it out for a test drive.

 

[JPaul]

Finally have the rear axle back in. Took me until 4AM to get it all finished, though that included replacing the front swaybar links. Those ACDelco "professional" links are apparently pieces of garbage. The driver side was completely sheared off the studs, and the passenger side's lower stud just spun in the ball joint (it has flats to use to remove/install the nut, that part kept still while the stud itself spun...)

Had to wait until this morning to run to Lowes and then Home Depot to get new metric bolts for the diff cover since ARB only includes standard threaded bolts with the cover for the GM 10 bolt. Got that all done and lube in it, jacked the rear up and put the transmission in neutral and spun everything by hand to make sure lube was on everything before I took it for a drive. Drove it around the block and everything seems to be OK.

I'm going to drive it until Tuesday and then change the fluid before I leave for Overland Expo on Wednesday. I was just going to leave Thursday morning but KC Hilites is having a shindig Thursday afternoon at their place that is not too far from the Expo, so I am going to go to that and just drive partway down Wednesday and camp overnight somewhere, then head the rest of the way down Thursday morning. It'll make the trip more enjoyable so I am looking forward to it.

I have the front diff with the shop to get matching 4.56 gears and the new front ARB locker installed. Just going to drive in RWD until that is all ready. I'm just glad to have the H3 back on the road again.

 

[JPaul]

Two days of driving so far and I think it's working out well. Pretty sure most of the noise I hear is my Duratracs showing their age, plus I tweaked everything pretty well apparently.

Glove box now barely brushes against the passenger door, there's a creak when stopping and starting as the weight of the nose of the truck shifts up and down, the front bumper is ~1/2" higher on the passenger side than on the driver side (or the body is lower now, one of the two), the upper radiator bracket is now turned at an angle (used to be perpendicular to the radiator and support, so the passenger side of the radiator is probably higher than it used to be or something that is causing it to shift over), rear door looks a bit cockeyed, driver side tail lamp isn't staying snapped into place anymore, etc, etc. Oh well. Play stupid games, win stupid prizes. I am pretty sure I know exactly when I tweaked the front corner, and yes it was while doing something stupid. The rear on the other hand I'm not so sure about, but it was likely during the same incident. Really I am surprised I didn't actually break more stuff, especially nothing on the front aside from the swaybar links. When I drained the fluid from the front diff to pull it I saw no indication of any issues, so that was good to see. The rest of the issues I'll eventually work through.


Also fixed the AC today with putting in the new condenser. I still need to put another 120 grams of refrigerant in but it's blowing cold air again. I think I have it working better than before even, but by the time I finally got to the point of actually charging it the ambient temps were down below 70 so it's hard to say for sure, I was getting 44 degree air out of the vents. We'll see how it is tomorrow during the day when it's warmer.

Still need to get the truck cleaned out and start getting packed for the trip to Overland Expo, I was hoping to have done that today but it took so long to get the AC done thanks to not having the right seals, needing a wrench to get the fan clutch off so that I could have room to get the new condenser in, the first OReilly's giving me a gauge set and vacuum pump that both had issues so then I had to go back out to return them and drive to another store to get ones that weren't buggered up, blah blah blah.

Oh, and I discovered that Les Schwab did a crap job on my alignment and didn't torque down the upper control arm bolts enough so they started slipping and causing everything to go out of alignment. You could see where the adjustment cams started out because it was relatively clean where they used to be. So I used the clean spots as a guide and put everything back in place and made sure the bolts were properly torqued down. I am going to get it re-aligned after I get the steering rack swapped and the front drivetrain back in, and I will definitely be taking it somewhere else then. May just try doing it myself, it's really not all that hard from what I have researched and I am tired of botched work.

 

[JPaul]

Truck did great going down and back from Overland Expo West. I had a lot of fun, got to meet Ronny Dahl as well as some new friends that I camped next to.

Still have lots to do, not the least of which is replacing the steering system amd getting the front axle back in. But man those 4.56 gears are worth it. I think that with the V8 the 4.56 gears put it back into its powerband compared to the stock 4.10 gears. I have not noticed any degradation to my fuel economy, and on the highway up hills it hasn't downshifted into 2nd yet, even with towing a decent sized load up to my storage unit this morning.

I'm waiting until I get the front axle in and broken in before I really let loose on it, but so far it's been a really nice improvement. I am beginning to think that the 4.10's were probably more meant to be used with the stock 31 inch tires, but when you add the Adventure package it moves up to 33 inch tires but they don't change the gearing in the axles. Seems like if I went to 35's I would want to go to 4.88 or something, but the front diff won't take anything over 4.56 so that is the limiting factor.

There is rumor of a HD front diff coming out from someone this summer for the H3, so maybe that will open up that possibility, otherwise I'd have to go with a SAS.

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[reaver]

I've been following your build for a while, but haven't commented until now. The very first Pic in this post cracks me up. Duvall is my home town. My parents still live out there.

Love the alpha build though.

 

[BPD53]

There is rumor of a HD front diff coming out from someone this summer for the H3, so maybe that will open up that possibility, otherwise I'd have to go with a SAS.

I'm currently trying to piece together parts for a SAS but a HD front differential could help a lot of people.

Where are these HD front diff rumors coming from?

I'll believe it when I see it. ? The H3 and Colorado have been a bastard in the off road world from the beginning. Seems to me that if something was going to happen it would have happened already.