GCC Spec 80s with H4 Button…what does it do?

[TXinVA]

I’m shopping around for an 80 while I’m stationed in Bahrain. Every one I’ve looked at so far (2x automatic, 1x manual) has an H4 button in where the CDL switch is normally located. I’ve asked for help in the Importing forum, but no help there. Hoping some of you GCC residents here can help me out.
What does that H4 button do? Are the GCC 80s not full-time 4WD, like the 60s? All three trucks I’ve seen, the H4 button doesn’t indicate anything at all on the instrument cluster, and I haven’t crawled under in the dirty street/sand parking lots during rainy season to grab the front driveshaft.
GCC residents, is there anything I need to keep an eye out for while I’m on the hunt?

 

[logicbyondreaso]

And just to be perfectly clear, this is different from "CDL" because there's still no centre differential to lock. All this H4 button does is drive a motor actuator to enable the front prop shaft. So instead of the traditional "H2, H4, N, L4" shift pattern on the lever, you end up with "H, N, L4". So the switch between H2/H4 is electronically controlled.

Looking to replace both driveshafts (propeller shafts). Current configuration is HF1A with H151 gearbox. When I look up by VIN the rear prop shaft comes up with 3 options. 1 can quickly eliminate because its not full time 4WD, but not sure what the difference is between other two. Only thing that stands out is that 60440 has "W(*CDL)". I have the H4 button does mean I have CDL? What shaft is correct?
37110-60440 vs 37110-60450

 

[DivByZero]

Looking to replace both driveshafts (propeller shafts). Current configuration is HF1A with H151 gearbox. When I look up by VIN the rear prop shaft comes up with 3 options. 1 can quickly eliminate because its not full time 4WD, but not sure what the difference is between other two. Only thing that stands out is that 60440 has "W(*CDL)". I have the H4 button does mean I have CDL? What shaft is correct?
37110-60440 vs 37110-60450

View attachment 3782443
View attachment 3782444
View attachment 3782445

There are three different rear prop shafts for the manuals, which are different lengths, corresponding to the different physical lengths from the back of the transfer case to the rear diff, depending on the transfer type. Since the rear extension housing differs in length for each type the lengths are different. They are as follows:
37110-60450 - Use with HF1A
37110-60440 - Use with HF2A
37110-60610 - Use with HF2AV

If you do in fact have a HF1A transfer, be it motor-operated L4 operation or not, with no centre differential and a fixed 50/50 power distribution front to rear, you want the 37110-60450. I know this is correct, because I ordered a brand new one myself a couple of years back for my HZJ80 with a HF1A.

 

[logicbyondreaso]

There are three different rear prop shafts for the manuals, which are different lengths, corresponding to the different physical lengths from the back of the transfer case to the rear diff, depending on the transfer type. Since the rear extension housing differs in length for each type the lengths are different. They are as follows:
37110-60450 - Use with HF1A
37110-60440 - Use with HF2A
37110-60610 - Use with HF2AV

If you do in fact have a HF1A transfer, be it motor-operated L4 operation or not, with no centre differential and a fixed 50/50 power distribution front to rear, you want the 37110-60450. I know this is correct, because I ordered a brand new one myself a couple of years back for my HZJ80 with a HF1A.

Thank you for posting this and your purchasing part number.
Here is what I have. Looks like HF1A.

 

[DivByZero]

Yep, that's a HF1A. Rear extension housing is stubby.

 

[SteelHunterFJ80]

And just to be perfectly clear, this is different from "CDL" because there's still no centre differential to lock. All this H4 button does is drive a motor actuator to enable the front prop shaft. So instead of the traditional "H2, H4, N, L4" shift pattern on the lever, you end up with "H, N, L4". So the switch between H2/H4 is electronically controlled.

Great information here! Thanks for contributing @DivByZero

Got a few clarification questions. So in your explanation above does this mean that the front prop isn't spinning until engaged via the H4 button? And since it didn't have a CDL does that mean it doesn't chirp if turning in tight corners on firm ground? Lastly what is this transfer case your referencing? The H1FA with electric actuator?

Oh and can you repost the manuals for the H1FA and H2FA.... I have both and am trying to figure out which one is best for my needs. Knowing how each operates would go a long way in my decision. And I'll need to regear whichever one I pick with 10% over and under drive. I'm leaning towards the H1FA as I'm not sure in the H2FA has synchros to shift on the fly whereas your snippet of the manual says the H1FA can. The H2FA is from Spain originally and its off a 1994 HDJ80. I'm pretty sure it's engaged electronically.

@mudgudgeon feel to chime in with your experience as well.