Transmission and Transfer Case Upgrade Options

[bartmanS4]

Ugh, there's work to be done.
So you may or may not know my VX. It has been highly modified over the years to include the AR5 5 speed conversion and I ditched the TOD in favor of a manual 2hi, 4hi, 4lo transfer case from the mid '90s Rodeo. This allows for the revolution 3:1 gear reduction mod to achieve a much better final crawl ratio. Unfortunately this TC is now popping out of 4lo to the point I can barely even hold it in gear with a strap and all my strength together. I've got another TC on the way and plan to swap the revo gears into that one. This should fix the issue until I wear out the replacement TC.
This has put me on a mission though to find a better solution. The two options I'm pondering are:

1) Hummer H3 manual trans mated to the NR6 - Borg Warner 4494 = 4.01:1 low range transfer case. This I think would work likely without changing the bell housing but that's easily done if needed. I think the input shaft dimensions are the same as the AR5. I would need to get the H3 transfer case control module for switching between 4hi and 4lo or wire another solution for controlling the TC shift motor. Unknown is the clutch and flywheel compatibility.
Pros: Good source though small numbers of later model transmissions. Robust 4:1 TC option with planetary gearing. Likely bolt on at the input side.
Cons: The 4:1 TC option is more limited hence more expensive. TC has a weak nylon internal shifter fork in the ~2009 and older cases that needs to be upgraded to an aluminum one, output side will need custom drive and prop shafts created.

2) Jeep AX15 five speed mated with a flipped NP231 or more likely a Dana D300 TC. Input shaft is shorter on the AX15 so extended pilot bearing would need to be sourced and possibly machined. Unknown is the clutch and flywheel compatibility.
Pros: Lots of part to choose from. Lots of aftermarket products available. Fully mechanical shifter setup. 4:1 TC gearing also available. Mating options for TC well sorted out and supported.
Cons: More customization necessary since the input side will need to be custom too. Output side will need custom drive and prop shafts created although more support available for this than with the H3 setup.

I'm sure there's more things that I haven't though of yet and problems I'll run into but I think it's worth the effort. I'm really leaning towards the H3 AR5/NR6.

[bartmanS4]

I have ordered both the H3 transmission and transfer case. We'll have to see how this plays out.

[bartmanS4]

So, I have the MA5 transmission and the NR6 transfer case along with the shifter motor now. I went through the TC to see if it needed anything, it doesn't. These transfer cases were originally manufactured with a nylon shifter fork but this one does have the aluminum or magnesium one so no problem there. This TC is a lot bigger than the TOD or manual TC that come in the Isuzu. The worry I have now is that the TC won't fit between the torsion bars, if it doesn't I'll have to make a custom clocking ring to rotate it down on the passenger side :-(

[fridaniki]

My Tranny went south and I have heard bad things about the 4l30e. Do you know if the 4l60e is compatible?

[Mile High VX]

It is not.

[bartmanS4]

I have fixed my Rodeo 3:1 transfer case by swapping in the Lo shifter fork and slide gear (don't know the actual name) from a spare transfer case I picked up at a junk yard. Since my 4lo is working again it has taken the pressure off for getting the H3 stuff installed so no rush now.

For clarity I will refer to the Trooper trans as the AR5 and the Hummer H3 as the MA5

I've been putting a list together of parts I'll need and there are few options on how to proceed and obstacles to completion as I see it:

1) Use the bell-housing and the clutch throw-out bearing fork assembly from my AR5 and that lets me use the original pressure plate.
However, it complicates the swap for anyone in the future because an AR5 is needed to complete the kit.

2) Use the input shaft that is currently on the MA5 which has a different spline count, 26 vs 24 for the AR5, length and bearing diameter. The H3 input shaft is a little bit shorter, not much but needs to be accounted for and the bearing surface diameter is smaller.
Pilot bearing for AR5 and MA5
AR5 MA5
OD 1.5748” 40mm OD 1.70” 43.3mm
ID 0.6693” 17.0mm ID 0.59” 15mm
Thick 0.7874” 20mm Thick 0.51” 13mm
Needs 1.5748” 40mm x 0.59 15mm x 0.7874” 20mm to match the outside diameter of the Trooper crank surface and the inside diameter of the H3 input shaft surface.
I believe a clutch for an 82-92 Camaro 5.0L will work but this needs to be confirmed.

3) Swap the AR5 input shaft into the MA5.
This would allow for all the stock Isuzu AR5 pieces to be reused. Again this complicates the swap for anyone in the future because an AR5 is needed to complete the kit. I'm also assuming the input shafts can be swapped and this assumption can probably only be confirmed by disassembly of both transmissions. The input shaft cannot be removed with the trans assembled as it has to come out from the inside.

4) Use the bell-housing and clutch throw-out piston assembly that comes with the MA5. This would hopefully negate the need for a spare AR5 donor however a usable matching push style pressure plate would need to be sourced along with any hydraulic line/linkage differences. I would prefer this approach but I'm not sure about the unknown obstacles to accomplish this.

5) Due to the larger size of the transfer case a custom clocking ring will likely be needed. How far down will the TC hang in order to clear the passenger side torsion bar? If it is too far this could kill the project altogether as it would be too susceptible to damage while wheeling.

6) Is the MA5 speed sensor compatible with the Isuzu setup?

7) What else am I not considering?

[bartmanS4]

wish the 4l60e was compatible but unfortunately it's a different beast.

[fridaniki]

Thanks