Grenaded my transfer case the other day and am looking for something beefier. I have found that an np261hd(manual shift) or an np263hd(electronic shift) should bolt up. However I'm having trouble figuring out the electronic shift wiring.
The 4484 in the h2 has a 7 pin connector(5 for the encoder, 2 for the motor). The 263 has a 5 pin connector(3 for the encoder, 2 for the motor). Obviously I dont think that'll match up.

I did find an encoder/motor for 99-02 np263s with a 6 pin(encoder) + 2pin(motor). That could work assuming that the resistances inside the encoder are the same.

Does anyone have a schematic for the encoder circuit for the h2? And bonus points if you can find a schematic for a 12478096 encoder motor out of a 99-02 silverado. I would be ecstatic.



also PSA don't run ur 4484 with the front driveshaft out. The differential load is too much for it to handle.

 

will the origional encoder motor bolt up? if it does then its just a matter of confirming the indexing of the encoder is the same positioning on the other transfercase. ie neutral matches neutral and such. you can do it with the encoder not mounted to the TC but wired to the vehicle then manualy confirm the position on the transfer case as you move through the ranges using pliers or grips on the shaft to rotate it.

 

On the 263 the motor mounts in the area between the front driveshaft and the case. I don’t know if the h2’s thick motor design will fit in there. I will certainly try that first. I might be able to make a linkage so it sits on top of the case though. I’ll have to see when I get it.

The nice thing is that with the simple design of this t case I can use it even in 4wd without the motor attached. so I’ll have some time to screw around with a solution and not be without a vehicle.

 

Did you have the transfercase in 4Hi LOCK when you had the driveshaft out? We have driven many miles without front driveshaft with no issue when in 4hi lock

 

Gavin, sorry to hear about your T-case explosion. A couple of things, in the past I considered replacing the 4484 with the NP263HX then using an AAM 11.5 diff in the rear and an AAM 9.25 in the front. (2500HD parts) The front and rear diff would require some welding work for the brackets that hold it in place as it is different then H2 with the 2500HD. Also, the actuator for the front axle an control for the transfer case would need to be added. But this setup would be absolutely bullet proof with the ability to handle 900lbs of torque.

Predator in CA. can give you alot of info on this as this is the optional setup they use in their Duramax/H2 offering. I will see what I can find as far as schematics. I had the GM doc system on my old XP laptop which hasn't worked in years but maybe I can resurrect it.

 

yep. I took it apart and it shaved off the splines on the shaft that mates to the rear planetary carrier. You may not have issues driving it around normally but I certainly would try towing or dyno pulls or anything high stress.

in all fairness I was in 4lo with the diff locked. But I didn’t even get all the way stalled up before it broke.

 

Thanks for the offer on the schematics but with further investigation on how the encoders work, there is no possible way to make the swap. The np encoders use basically a potentiometer and the bw encoders are a glorified Hall effect sensor. The bw encoder rotates about 270 degrees between 4hiO and 4loL while the np encoder is less than 180, so there isn’t really a way to wire it up, and if I could, there’s no way to adjust the degree of rotation by adding resisters and what not.

The only two options are to find a tccm from a truck with this t case and figure out how to get the different switch design to work with it. That is if you can even program it to the 08 since the can bus is different. Or make a fancy linkage and remote mount the oem encoder. I’m gonna try option 2 and if that fails it’s getting a lever on the floor.

I would try and ask predator, but they’re 100% going to gatekeep that information.

the diff actuator might be pretty easy to install. A 2500hd diff can be found for under $300 on eBay. All I would have to do is swap the passenger tubes and cut/weld the mount. That’s a project for another day though. Step 1 is to get the thing driving again.

 

Gavin, I would give them a call anyway, good will on this forum for them will go a long way. When I was looking at what you are thinking about was for my 2006. The new canbus used in the 08/09 presents a bunch of issues and is not as user friendly as the old system was. One angle you might use with Predator is that your wanting to do the associated drive train work but once it done let them do the Duramax conversion. They might buy that, what the hell its worth a shot.

I wish I could talk wifey into a complete drive train upgrade to duramax on my 08 but that's not happening. I know the diffs, t-case and trans used on the 2500HD are worth the effort especially if your H2 is a forever vehicle and I share that sentiment. I might have some others in the Garage but the H2 will be there as long as I am breathing. While I doubt I will ever sell wifey on a D-Max, the 6.2 might accidentally wear out and need a 6.6 replacement, lol. Keep us all posted with your upgrade status, your probably one of the most active forum members with 08/9 upgrades.