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Discussion Starter · #1 ·
Weird question, I know, but bear with me.

I once had a Toyota Tacoma TRD that had the factory locking rear differential. In stock form, you could only engage the rear locker when the truck was in 4-LO.

I did what is called "The Grey Wire" mod, where you open up the kick panel, find "the grey wire" and ground it. This made the locker think that the transmission was in 4-LO, and allowed you to turn the locker on anytime you wanted. It was nice to be able to do snow wheeling and be able to lock the rear in 4-HIGH where you needed wheel speed. It also made for some sweet 2-HI, rear locked, supercharged donuts, but that is a different story.

Anyway, on my '99 Amigo, I can only shift the transfer case into 4-LO when the 4wd is already engaged. I figured since it is a push botton system, perhaps I can trick the transfer case into thinking that the 4wd is engaged all the time, then I could use 2-LO if I ever wanted to.

Thoughts?

P.S. In the Toyota, doing this mod didn't affect the drivability of the truck at all. No codes, no 4wd indicator light, nothing.
 

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you want to shift into 4LO whilst moving??

be prepared for loud crunching, snapping, or a hole in the floor
 

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ah, reread... manual hubs work well, just unlock, and you have 2LO
 

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Yours is like what I had before I put the solid axle in. There's a cylinoid/servo on the front axle that locks in with the button part. Then the t case shifter does hi /low only so if you want to stay in two wheel drive or I guess disable that front cylinoid maybe with an inline switch or put hubs on you get what ya get.....
 

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chikoroll said:
ah, reread... manual hubs work well, just unlock, and you have 2LO
yea that works great especially if you are in a manual and your hauling heavy loads or if your learning to drive stick it really helped me this summer when i was learning to drive stick and hauling big loads of wood in my gpas toyota
 

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Discussion Starter · #8 ·
bradzuzu said:
Yours is like what I had before I put the solid axle in. There's a cylinoid/servo on the front axle that locks in with the button part. Then the t case shifter does hi /low only so if you want to stay in two wheel drive or I guess disable that front cylinoid maybe with an inline switch or put hubs on you get what ya get.....
Hmmm, seems like you could interrupt the signal between the solenoid and the transfer case and trick the transfer case without effecting the 4wd function.
 

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Probably could get away with that. You could even use grey wire :).
My four wheel drive light blinks when I engage the 4x4 button, just because it doesn't get signal from up front anymore. Off like normal when in 2x. Yours being 99 I think is still a vacume servo so you could even iterruped the hose with a ball valve.
 

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This was just on Trucks! the other day. Cool effective mod on the Tacoma.

I don't think you could do this on a Zu without hubs. But yours is also a newer Amigo, so maybe there is more confuser (computer) parts in there.
 

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It doesn't have to be complicated ,just go out to the wiring harness at the shift modual there's a plug in conection bellow the A arm on the drivers side. I think there are 4 or 5 wires two for the light indication and the other two or three do the actuating. Find that wire group and cut and feed your switch into that. As I'm writing this I think that vacuum holds it disconnected. So when the vehicle is shut off it bleeds off vacuum and locks in. On initial starting it unlocks probably a factory set up so parts stay lubed. I think though that interrupting that wire would/should still work.....:)
 

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Discussion Starter · #12 ·
I don't have a natural knack for this kind of thing, but the way I'd reason it out, is to start by finding out how the transfer case knows that 4wd has been engaged. As long as it is not mechanical, it seems like it'd be possible (maybe not easy) to recreate the signal.

So the question is, what exactly notifies the transfer case that 4wd has been engaged?
 

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Using 2L is real easy and doesn't require any mods. I have done it many times with my daughter's 1998 Rodeo. Just hit the 4wd button to go into 4H. Shift to 4L (you cannot do this unless 4wd is engaged). Release the 4wd button to take it out of 4wd. Since the transfer case is still in low range, you are now in 2L. The green light will blink but it works just fine. If you start to slip just hit the 4wd button (even while moving) and you are back in 4L. To get out of the low range, you must first engage 4wd or else you will not be able to move the lever into high range.

The reason this works is that the 4wd button controls a solenoid on the driver's side front axle. In 4wd the axle is locked. In 2wd the axle is unlocked. With an open front dif, the unlocked axle gets all of the power. The 4wd button also unlocks the transfer case and allow it to be shifted.
 
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Are you sure the servo in the t case isn't trying to disengage/oporate when the button is pushed again in the off mode. I played around with that to and if you pull the shifter back to high it makes the lock out make a quick clack sound internally.
 

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Any time I hit the button, I can hear a click in the transfer case which is related to either engaging or disengaging the front drive shaft. I wouldn't call it a clank but you might.

I honestly do not know if the front drive shaft spins or not with the transfer case in Low and the 4wd disengaged. It doesn't really matter as long as the front axle is disengaged, you are still in 2L. I suppose that you can lift the car and try it to find out or ask Jerry if you are curious. I just know it works.
 

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94Rodayo4x4 said:
This was just on Trucks! the other day. Cool effective mod on the Tacoma.

I don't think you could do this on a Zu without hubs. But yours is also a newer Amigo, so maybe there is more confuser (computer) parts in there.
Yeah i saw that too. I was like OMG I KNOW WHAT HES TALKING ABOUT! lol
 

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I'm sure your right the t case will engage and spin the front drive line. and by pushing the button would release the front coupling. I pulled my shifter back into hi and it came out but the light kept blinking. I finally just shut it off and started it back up and no more light. I just don't know how the t case servo operates if once you've pushed the button if it's trying to actuate the lock out between hi and low.
It may have been different on my 2000 because the front was another electric servo motor.
 

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the transfer case on your amigo is engaged all the time. This is why people say manual hubs are useful. You're essentiall running on 3wd, with the 3rd being the passanger front. What engages the 4th wheel(drivers front) is the actuator on the drivers side. IT's operated with vacuum lines. There is a sensor that detects the position of the actuator so you just have to figure something out with that. There are also sensors that control the vacuum lines so I'm not sure if these will need fooling too or not, if that is possible. Like it was suggested manual hubs will not only let you get the 2wd lo you want but also save a lot of time and headache as well as wear.
 

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I don't think the t case is spinning the front drive line until you push the button and then the t case servo locks it in??? Then about the same time the servo up front locks in coupling the left axle to the third member. The outer axles spin at all times unless you get hubs. That's how everything sinc's and locks in. Hubs for sure would be a cure with out anything being damaged.
 
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