Transfer Case

Call me crazy but I think imagination is a good thing :thumbs:

Today I called northwest fab...Just kicking around options. At the end of the day I dont feel the 100+:1 crawl ratio is a must but it would be cool to have for the tougher trails, while I probably wont have that type of gearing for a while I just like researching things and keeping options open. While changing out different t cases is no big deal to the old heeps to us its a big deal. Those damn electronics...So I toyed with the idea of using something called the blackbox-i. After speaking with the guys over there I found out that they think the blackbox-i can work with the H3. The blackbox is a reduction unit, like a doubler but only pushes the t case back a little bit vs. adding another transfer case like the doubler kits. The blackbox is a 2spd with gear ratios high (1:1) and low (2.72:1) so even keeping the current non adv case (2.64:1) would give me a great ratio of 100.1:1 (3.059 x2.7 x 2.64 x 4.56) Some issues that can and will arise is first off electronics, we dont think this will be an issue seeing that the stock case will still be there, my low range speedo will be off though. driveshafts length is another concern...the front one will be longer which is ok but the rear will be shorter which can cause too much of an angle on the driveline and lastly crossmembers. The crossmembers will need to be moved back and/or notched so everything will clear.

http://northwestfab.3dcartstores.com/NWF-BlackBox-Underdrive_c_7.html

The main concern for me is crossmembers, after some measurements you can move the t case mount crossmember without too much concern but the 2nd crossmember is a concern as it does house the torsion bars...The t case would hit that crossmember and would probably have to be notched. Also if you removed the torsion bars and went with coilovers you could move the crossmember but back only 4.5inches until hitting the gas tank.

Now NW fab threw another idea out which could be used IF we found out the electronic issues first. Using a dana300 t case with the blackbox it could work as it is a much shorter unit so the crossmembers wouldnt have to be moved and then all that would have to change was mounts. A dana300 is found in a passenger drop which is what an H3 needs. I think overall a 100:1 crawl ratio would be awesome but not too overpowering to the point where you couldnt even stop the rig when braking.

I just wanted to throw this up for discussion as these H3s are getting older (mines almost 7 now!) and in a few years after college if I look for a 2010 H3 good ole squeaky could become a dedicated trail rig. So whatcha guys think? this could be an alternative to the atlas...

If AA would just make this piece for a 4l60E and a BW 4493 or 4494 then NO modifications would have to be made as it just replaces the bellhousing. I cant blame them though, they are out there to make money and jeep aftermarket will make you money while the Hummer aftermarket is quite limiting in terms of profit.

http://www.advanceadapters.com/products/rubi-crawler-planetary-crawl-box/

You can't buy the 4:1 Adventure Case?

Your crawl Ratio with a 4:1 will be just under 120:1 (you have to take into account the Torque Converter in Low Range) Hummer doesn't calculate it that way. They calculate the Manual and auto the same.

I'll see if I can find the formula...

O wow! I didn't know that...I didn't know the torque converter added so much

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Oh and AA does make an Adapter for the 4L60E - you'll just have to add sticks. But the same would go for a NP or Dana T-Case with the Klune-V. It's all the same...just different.

The badass thing about our BW is that it's the only 4:1 Low range Electronically Selectable t-case out there. Even Heeps have to use a stick.

Now that's sweet!

I wish AA never dropped the electronic shift program...hopefully they will bring that back one day

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bebe said:

our BW is that it's the only 4:1 Low range Electronically Selectable t-case out there. Even Heeps have to use a stick.

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You say that like it's a good thing??????:wink:

After a weekend in Moab without 4L & then having it randomly kick out on me last weekend twice... I'm not seeing that as a positive!!!


I've very interested in this though, I really need to get a lower crawl ratio.

I have never had a t case shifting issue...luckily *knocking on wood*

The only issue with a doubled t-case combined with an electronically shifted trans is that no PCM or TCM that I know of can accommodate multiple low ranges. If you put a 2.72 crawler box in front of your 2.64 BW case, your PCM will possibly have issues with 2.72, and it will definitely freak out and not shift in 7.18 double low range. This can be worked around by someone who knows what they are doing.

Even if the 2.72 was a manual shifter? Couldn't you throw the 2.64 into low then then shift the blackbox into low?

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Doesn't matter. The PCM is programmed to compensate for a 2.64 reduction at the output speed sensor. When you shift into double low the output will spin 7.18x slower than the trans output, but the PCM will be expecting a 2.64x reduction. The PCM will see this very slow speed and won't shift out of 1st gear. This is fine as long as you don't want or need to shift out of 1st in double low. Otherwise, it's a problem.

When I did my build, one of the things we looked into was adding a Klune-V. In the end we didn't for all the reasons explained by Max. I would be one happy camper if I could get rid of the electronic BW transfer and get something more reliable like an Atlas. I'll take manual shift levers any day!


"Ex Umbris Venimus"

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MaxPF said:

Doesn't matter. The PCM is programmed to compensate for a 2.64 reduction at the output speed sensor. When you shift into double low the output will spin 7.18x slower than the trans output, but the PCM will be expecting a 2.64x reduction. The PCM will see this very slow speed and won't shift out of 1st gear. This is fine as long as you don't want or need to shift out of 1st in double low. Otherwise, it's a problem.

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I don't know if the H3 is like my H2, but if it is you should at least have second gear as well by manually shifting it. In my H2 if I put it in 1, it stays there. In 2 it starts in 2 and wont shift up. In 3 it starts in 1st and will auto shift up and down but wont go above 3rd.

ReconH3 said:

When I did my build, one of the things we looked into was adding a Klune-V. In the end we didn't for all the reasons explained by Max. I would be one happy camper if I could get rid of the electronic BW transfer and get something more reliable like an Atlas. I'll take manual shift levers any day!

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How easy it is depends on the PCM or TCM, as the case may be. More specifically, how does the PCM/TCM get notified that the t-case is in low range. The Gen III LS PCM's are simple - the have a dedicated input that you simply ground to tell the PCM the case is in low range. The PCM itself can be programmed for low range ratios from 1:1 to 8:1. If the Atlas PCM is the same way, then it should be pretty straightforward. OTOH, if the PCM or TCM (later vehicles) gets 4-low notification via GMLAN from the TCCM, then it gets a bit more complicated. It gets more complicated still with a 3 or 4 speed t-case setup. There will inevitably be some compromises, but anything is doable.

Scarsman said:

I don't know if the H3 is like my H2, but if it is you should at least have second gear as well by manually shifting it. In my H2 if I put it in 1, it stays there. In 2 it starts in 2 and wont shift up. In 3 it starts in 1st and will auto shift up and down but wont go above 3rd.

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I have no idea. But I'm sure that someone on here owns an automatic H3 and can enlighten us...

So for me being a 5 spd, would there be some other issues that it would cause?

Being a little underpowered when I'm at high altitude getting as low as possible would be a serious help on the nasty stuff.

MaxPF said:

Doesn't matter. The PCM is programmed to compensate for a 2.64 reduction at the output speed sensor. When you shift into double low the output will spin 7.18x slower than the trans output, but the PCM will be expecting a 2.64x reduction. The PCM will see this very slow speed and won't shift out of 1st gear. This is fine as long as you don't want or need to shift out of 1st in double low. Otherwise, it's a problem.

Click to expand...

Scarsman said:

I don't know if the H3 is like my H2, but if it is you should at least have second gear as well by manually shifting it. In my H2 if I put it in 1, it stays there. In 2 it starts in 2 and wont shift up. In 3 it starts in 1st and will auto shift up and down but wont go above 3rd.

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MaxPF said:

I have no idea. But I'm sure that someone on here owns an automatic H3 and can enlighten us...

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You two are talking about two totally different scenarios, one stock and one with a doubler.

Both vehicles have 2 speed BW cases, the H3 has 2 versions and the H2 has 1. The H3 is the only one that has a 4:1 option.And both BW cases, or I should say all three) shift/operate they way Scarsman describes.

The doubler couldn't be operated electronically unless you had an Aux switch, I would want to have a stick shift for it.They can be a bit of a pain to get in and out of gear.

This conversation always turns into a bit of a mess, because as many brains as I have had consider this, there is no easy way to do it. You're gonna end up cutting the floor and you're gonna piss of the electronics. That's why I haven't done it yet either What we have is already awesome, and none of us are out racing these things. What we have is sufficient for what we do.

If you want to feel sorry for someone feel sorry for speedy, there are no decent low range options for the FZJ80, so it's going to get completely changed around next season.:wink:

backcountryislife said:

So for me being a 5 spd, would there be some other issues that it would cause?

Being a little underpowered when I'm at high altitude getting as low as possible would be a serious help on the nasty stuff.

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For you , there is no help :giggle:

J/K, I have no idea about the Manual, I'd have to see if all the VSS's are in the same place. But one would think a doubler would be easier to pull off in a manual vs auto. You would just lose function in all your buttons. And I think you could recalibrate the VSS/PCM speak.

bebe said:

For you , there is no help :giggle:

J/K, I have no idea about the Manual, I'd have to see if all the VSS's are in the same place. But one would think a doubler would be easier to pull off in a manual vs auto. You would just lose function in all your buttons. And I think you could recalibrate the VSS/PCM speak.

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so, you're saying that I need a new vss/ pcm... Yeah, that's what I was thinking too...

I just want to go slower... mmmkay?

It seems like just putting a 4:1 t-case in is the simplest way to go about this huh?

Yes....that's the jist of it.

How tough are these BW's when you really pound them through the tougher trails?

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06 H3 said:

How tough are these BW's when you really pound them through the tougher trails?

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I didn't have an issue until my first trip on Fordyce, and that was being stuck in a snowstorm, trying to get up boulders covered in snow and ice. But I still got off the trail, replaced under warranty. And my second, it never went, I could just tell it wasn't healthy (wobbly shafts) so I bought a new one.

Ask some hardcore heepers how often they break T-cases...as much if not more than we do. T-cases break. Marlin Crawlers break, Klune-V's break,even Atlas's break. When you wheel hard, **** breaks.

That is all. :cheers:

Speaking of breaking stuff, have you blown up your rear 10b yet? 'Cause I got something to replace it if you're still interested :deal:

I know that question is for Bebe but when swapping out the rear axle is going to require custom tone rings right? Gotta keep the computers happy!

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The rear axle has tone rings on each hub? If so, then yes.

Yes to Max and yes to Chris.

I am definitely still interested. Ill pay you to haul it to Moab, or I can swing through Az on my way out in October. I have to stop in Glendale on the way through.

I will PM you in the next day or two and we can work out details without further hijacking this thread :thumbs: