I was at a car show a few weeks ago with the beast when I struck up a conversation with a past H2 owner, looking over my 08 he shared with me his experiences he had with his 08. I found it interesting and questioned if it was true or bull, here it goes.

He mentioned he had an 08 with some front drive train noise he was having difficulties locating so here's what he did. First he removed the front drive shaft and both front half shafts, locked the 4wd in high lock and drove it around.
First I didn't think you could just remove the front half shafts at the hub without the front wheel falling off. Ok, lets say that works, He said the driveability of the H2 was so much better, quieter, handled better and got better fuel economy.

Ok, true what he did would remove power from the front axle and locking in high would remove the need for the 40/60 back force required for the transder case to do it job. Locking in 4wd high would still provide power to the rear axle.

With all of that said now comes the next part. He said he was so impressed he wanted to take the next step, He picked up a front axle and transfer case out of a GM 2500HD, Had the 2500HD axle modified to bolt into the H2, installed the
2500HD transfer case, changed up the wiring on the activator and had the BCM reprogrammed. Since the new front axle was 4:10 ratio he changed the rear ratio to 4:10 as well.

When it was all done he could fully deactivate the front differential, front driveshalf and run in true 2wd. With the new ratio and upgrade to 2wd he said he gained over 2 mpg and was about 1.5 seconds quicker in the quarter mile.

I asked him if he still had it and was told he sold it to A&L Imports back when the price of H2's were through the roof.

So what do you think all? Fact or Fiction, Since Predator is able to upgrade a Gas to Duramax I would not think this would be as difficult and it seems possible and much more cost effective then switching over to a Diesel.

 

Most importantly… he can do burnouts now!
I would entirely believe in the 2mpg increase, 1.5s in the quarter mile… he’s dreaming. 1.5 in a 1/4 mile is an eternity. He’s probably just a 💩 driver.(not saying I could do any better). There’s a reason most manufacturers disconnect the hubs when not in 4wd. Because the differential and driveshaft have a lot of rotating mass that take a lot of energy to spin

 

Contact George 631 226 1448 @ Transfercase Unlimited for a 2WD H2 conversion if interested.

 

Tainter, is that transfer case for a 4l or 6l series trans and what vehicle did it come from? thx

 

I'm currently doing my 5th Duramax/Allison conversion with LBZ (best for 03-07 H2's conversions) and can shed some light on your post. My 4th conversion (i still own/drive) retains the AWD (first of it's kind, I believe) and it's on 3.73 gears, also a fist I believe. All previous conversions, I used the 2500HD doner transfer case and was a 2WD switchable to 4H and 4L. (Me personally prefer AWD).

Had he been better informed, he could have saved time and money by keeping his front differential, which is already 3.73 on the 08-09 h2's, and only bought passenger side of clam shell diff case that has mount for actuator, retain passenger H2 axle housing.

Because I've not yet done an 08-09 conversion GMT900 Platform (I have an 08 next in line) so I can't be 100% certain but believe it follows same principles as the 03-07 I've done.
That said, From the 2500HD, he would need the TCCM and switches then rewire both and include front actuator, he should be good to go. There would be no need to program the BCM and I'm not sure that is even possible.

Error: in my tutorial, I was thinking of my last conversion where I kept AWD. To switch to 2WD option, the axle tube that is necessary is NOT the H2's but rather the 2500's. You will need to adapt the axle tube mount to fit the H2's frame mount. A very bad example is the one circled. I paid someone who claimed they knew how to do a H2 Duramax swap way back, when I was doing my first conversion. If your H2's passenger side diff clam shell does not have the hole drilled for actuator, you will either drill it or buy one that does. I've only seen 1 H2 diff without the hole. I can include a picture once I get to that part on my current conversion, if any interest.