2 Wheel Drive H3

[reaper]

Thought I'd post this seperately... most of you might know this but I didn't until 06h3 posted it.

If you have issues with your front driveshaft: you can simply remove it and drive home. It drives really nice in 2 wheel drive. You should select 4 wheel lock which locks the hubs (the non-existent driveshaft to the rear driveshaft). This happened to me on the way home.... I wish I would have just pulled it immediately. But I did get a bonus vacation day out of it, so it's all good.

The rear driveshaft you kinda need, as it seals the transfer case... but with no front driveshaft everything is still sealed up and happy. I drove a few hundred miles home without it, and it drives REALLY NICE on the freeway. You could probably even drive around in 2 wheel drive for fuel economy if your h3 is a daily driver.

 

[4speedfunk]

Yes and no. Yes...this method works great, and you can drive all you want without a front driveshaft. But, no...4HI-Lock has nothing to do with the hubs.

Like you said...all you gotta do is put the T-case in 4HI-Lock and pull the front shaft. It causes no measurable harm, and it will get you home if you have a screwed up front driveshaft. You're merely putting the t-case into lock mode which splits the torque 50/50, and defeats any front-to-rear bias of power. This trick just happens to work because when you press the 4HI-Lock button...you are over-riding the computer. It no longer senses any difference in slip between the front and rear drivelines and the t-case will spin both output shafts equally. In essence...you "lock" the outputs together and tell the computer to ignore the fact that the front driveshaft is missing. (BTW...you can install a slip yoke eliminator on the rear output and use the same trick on the rear driveshaft). However, don't think this trick also works with a broken front diff....it does not! This is because the hubs on the H3 are live all the time, whether a driveshaft is installed or not!

Its important to note the difference between locked HUBS and a locked T-CASE. Some people might think that by performing the above procedure that the front axle is no longer turning. This is incorrect!...it is still turning even without a front driveshaft. The difference is...its not being "DRIVEN". Instead it is being "COASTED". You must remember that the hubs are fixed on the H3 and live all the time. So, even without a front driveshaft...the wheels themselves will still spin the front axle. To see what I mean...have a buddy lay down and look at the front diff as you slowly drive past. You will see the yoke (without a driveshaft connected) spinning just like normal. Its not a ghost!...its the hubs spinning the front axle because you can't disconnect them! So...its technically not 2WD, and you're wasting energy (fuel efficiency) pushing around the front diff...spinning it from the coast side of the teeth.

Understanding this difference between locked HUBS and locked T-CASE will be a big deal when you break a front differential. While you can limp home after a driveshaft failure, without further damage...the same trick does nothing to save a front axle failure. You will munch & crunch your front axle all the way home, even with the driveshaft removed. This is one situation where having un-locking hubs would be real nice. They allow you to shut-off the diff completely, and save some carnage. Its the achillies tendon of full-time 4wd's.

 

[bebe]

Yep - done it, and put over 5K miles on it. Better fuel mileage too

You can even do it for a broken front diff.

 

[4speedfunk]

Hey Bebe...didn't you drive around with the entire front end (half-shafts, and main axle) out? Just A-arms and hubs?

 

[skinner41]

Do you have to have stub shafts in the hubs to keep the bearings together?

 

[bebe]

Do you have to have stub shafts in the hubs to keep the bearings together?

I drove without the shafts for 450 miles, but you can keep them in without the R&P because they are c-clipped. Keeping the shafts in are the key - but it will get you off the trail and home without them (halfshafts).

Rick was going to make a plug kit, so if you break a shaft, don't throw away the outer, keep it for a plug/trail fix.

 

[bebe]

Hey Bebe...didn't you drive around with the entire front end (half-shafts, and main axle) out? Just A-arms and hubs?

I did, not for long, just so we could get home.

 

[4speedfunk]

I solved the hub-lock issue when I installed the SA. I'm now running manual lock-outs, so I can free-spin the hubs in just seconds. Now all I gotta do is figure out a way to shut-off the front driveshaft, without lighting up the dash! Hmmm... I need to check out some tractors.

 

[MTUH3]

The other trick I picked up on is there if you did not shift into 4 hi lock with the drive shaft in. Turn the truck off, turn the key to accessory mode, then push the hi lock button. The computer will get all confused and not shift to hi lock if the engine is on.

I drove put about 500 miles on mine with no prop shaft in the front, no problem. Last summer a guy blew his front diff, we pulled the front prop shaft and both half shafts and he drove home. Stuffed a couple rags and taped around the axle to keep the fluid from sprinkling the roadway home.

I did not try to go in and out of 4 lo, with the Adv pkg it allows you to keep using your locker, in case you still have a few obstacles to clear, but I assume it works the same way.

 

[snookeehook1@gmail.com]

Does anyone have or make a front hub converison kit so that I can have manual Hubs also I was told about a vjscus couplrt in the transfur will get destroyed or destroy somthing if I put manual hubs on the front of my hummer h3. Is there a convrrison kit for this is shat I need to know

 

[Scarsman]

There is no hub kit. And if you did manage to convert to manual hubs somehow you would have to change the transfer case as well, because the H3 is full time 4x4. Otherwise you would have to drive it in 4x4 all the time.

The H3 does not have a viscous coupler type transfer case. Those are seen with all wheel drive vehicles. The H3 is completely mechanical.

 

[host3400]

So the boot on my driveshaft was shot. I removed the driveshaft. Learned that you can drive in 4 high lock. I tried it and it worked. Drove off my ramps, went down the street about 75 yards, came to a stop sign and it seems as if it went out of 4 high lock, but with the indicator light still showing I was in 4 high lock. I had it pulled back to the house. I tried what you listed below, I'm still getting all the power to the front. I can hear it spinning. I turn the car off, put it to ACC, go to 4 high lock (hear a very slight click) and then start. Nothing. Additionally, 4 low lock does the same AND the car will roll even in park now.

Please help!

The other trick I picked up on is there if you did not shift into 4 hi lock with the drive shaft in. Turn the truck off, turn the key to accessory mode, then push the hi lock button. The computer will get all confused and not shift to hi lock if the engine is on.

I drove put about 500 miles on mine with no prop shaft in the front, no problem. Last summer a guy blew his front diff, we pulled the front prop shaft and both half shafts and he drove home. Stuffed a couple rags and taped around the axle to keep the fluid from sprinkling the roadway home.

I did not try to go in and out of 4 lo, with the Adv pkg it allows you to keep using your locker, in case you still have a few obstacles to clear, but I assume it works the same way.

 

[SuperBuickGuy]

sounds like you broke the well-known-because-it-fails shift fork. The good news is it doesn't cost a huge amount to fix it, the bad news is it's a hellofalot of work.

 

[host3400]

Thanks SBG. What's strange is that the truck was running just find. Had a rattle coming from the drive shaft, so ordered a new one and removed the old. Do you think merely pulling the drive shaft and swiching to 4 high lock coulf have done that? The weird part was that it went down the street find and then once I came to a stop and tried to go, nothing.

 

[RamRod]

I think it must have been like that for a while but you didn't notice until the front driveshaft was pulled


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[4speedfunk]

I'm confused as to what the problem is. Your truck will not stay in 4HI-lock?
For the record...your front output should be active all the time (you should hear it spin). Also you will not have a PARK gear with the front driveshaft removed, so make sure to use the parking brake. So all of that sounds okay.
The bigger question is why it doesn't stay in 4HI-lock. Perhaps it wasn't fully engaged? It takes some distance for the mode change to occur...and the mode indicated will flash during the transition. But once it lights solid...you should be good. So it sounds like a shift fork issue to me.

 

[4speedfunk]

Also...I think I may have the 2WD mode figured out. I need a donor t-case to experiment with.

 

[RamRod]

Also...I think I may have the 2WD mode figured out. I need a donor t-case to experiment with.

I will be pulling my tcase soon... I think it's just the fork that's giving me issue but if it's more then I might have a tcase to trade you [emoji12]

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[06 H3]

Cj I got one 2.64:1 been sitting in a crate in storage for years worked perfect when I pulled it

 

[4speedfunk]

I need one that was known to be good. 2.64:1 or 4.03:1....doesn't matter. Unfortunately, the mods I got planned will either work...or render the t-case useless! -haha.

The basic idea...
I want to modify the 4HI-Street mode inside the case, to make it 2WD (rear output only). This mode uses an inline differential that is much like a single-track axle diff....except it all operates on the same centerline (rather than 90-degrees apart, like an axle). If you've ever messed with single-track diffs, you know that the wheel with the least traction gets all the power. The Hummer t-case works the same way. If you've ever watched a Hummer get stuck in the mud...you'll see that the end with traction quits spinning, and all the power goes to the other axle. This is also why H3's don't move with a broken front axle. The diff inside the t-case thinks its spinning, and takes all the power off the rear output and sends it to the front. Its touted as being a 60/40 split but, it does vary all the way to 0/100 if conditions necessitate it. This variable split between the outputs is what makes the H3 so driveable in 4HI-Street. In tight corners...it varies itself so you don't feel the binding that normally occurs in a locked 4WD vehicle.

This variable device is entirely mechanical. There are no clutches or springs. There are no sensors or viscous devices. The variable dohinky assembly (or VDA) has a basket with a sun-gear and planetary gears, that vary the torque output going to each end of the vehicle. What I propose doing is taking the VDA apart...machining the teeth off of the front drive gear...then welding the rear drive gear so it is permanently connected. I am hoping this will result in converting the 4HI-Street mode to 2HI-Locked. When done...the 4HI-locked and 4LO-locked modes will hopefully be un-affected. Then when you hit the 4HI-Street mode...the fork activates the VDA like normal...however the teeth are gone from the front drive of the VDA, and the rear drive is welded solid to the VDA. Thus...2WD mode. Obviously, this means nothing to 99.9% of H3 owners but, it would be great for us with solid front axles and locking hubs. It would essentially be converted to a traditional 3-mode 2HI-4HI-4LO case.

I'm 99% sure there will be no electronic intervention with this mod. ABS, Traction Control, and Stabilitrac are all governed by computers, and enforced by the braking system. The self-sensing front/rear torque split of the t-case is entirely mechanical and dumb. It is not controlled by any electronic source that I can find. Best of all...this will require no levers, fabrication, or swapping. Its a mod that is entirely internal to the t-case and it would look and act just like stock from the outside. Given the choice...I would gladly trade the torque split 4HI-street mode, for a completely disconnected 2WD front axle. I have evolved (or de-volved, depending on how you look at it), to using my truck for two purposes...(1) driving around on the street or (2) full-on off-roading. I want 2WD or I want 4WD-Locked. Period. I simply do not want a full-time 4WD mode anymore.

The big concerns I have with trying this are...
Will the front output (driveshaft) remain static while the rear output is turning at 70mph? The idea is that the front diff, driveshaft, and output from the t-case are all motionless in 2WD.
If so...can the front output of the VDA survive this free-spinning situation for extended periods of time? This depends on what sort of bearing situation exists inside the VDA. No doubt the stock case is designed for occasional speed differences that occur between outputs, during the range of torque splitting (For example: 60/40, 70/30, 80/20, etc.). But, I'm not sure its designed for a 12-hour interstate trip with the font output completely motionless and the rear output screaming away at 70 mph (100/0 split). Possibly staying this way for months at a time.

Only one way to find out.

 

[06 H3]

I have a working 2.64:1 t case that's been sitting, have it! Try it...or if u want me to I can. Never messed with these t cases before though. I guess I have a few questions.
#1 can the welds withstand the abuse? Is it big area that offers a lot of weldable surface?

#2 Why wouldn't the the Front output bearings last? Seeing everything else is spinning and flinging fluid everywhere wouldn't it keep it lubricated.

 

[06 H3]

Also, I do believe it will benefit to a degree to H3 ifs owners. That front axle is a tiny axle and has no business running under an H3 but with 4wd street mode that diff is taking daily abuse, not much but amplify that daily for years and years, the bearings and R&P see load on and off all the time, in 2wd mode it will not see any load. It will spin but it will spin freely without any torque being transmitted to the axle and that should hopefully allow things to last a little bit longer so when it comes time to wheel and your putting the max abuse it will see it will have fresher less worn parts.

 

[cgalpha08]

Won't the front spin anyway as you move due to their not being any axle hubs in the front that unlock it?

 

[4speedfunk]

Cg...yes. I think that is what 06 was talking about. If you really really really wanted to...you could convert to a Colorado/Canyon IFS front axle. It has a CAD (Center Axle Disconnect) that you could wire to a manual switch. A CAD is not a true hub disconnect, but all the modern part time 4x4s use them.

 

[4speedfunk]

06...not sure on the welding. It would be the equivalent of welding spiders to make a locker. Or possibly disassemble it...cut a key way...and reinforce the key with weld.