Thoughts on TOD disconnect

Hello,

I was comparing the VX and Trooper "TOD systems", and I've noticed that Trooper got some extra "pneumo-electronic" valve, or even two, that are purposed to disconnect the TOD box on-the-fly. It is called "shift on the fly" (if I remember it correctly).

So, lets say we have VX's TOD "disconnected", in other words, the TOD clutch is not engaged, and we have manual hubs installed and unlocked.
Then, when the car is moving, the clutch disks that are "connected" to the rear wheels are spinning, while disks that are driving the front wheels are not. Or at least not suppose to... But, we have an oil inside the TOD. And this situation will create a friction in between "rear" and "front" discs, that will create heat and extra fuel consumption.
Maybe thats why Isuzu engineers designed an extra component to disconnect the TOD box?

What do you think?

Another thing is -- the common recommendation for disconnection the TOD, includes manipulations with "blue" or "light blue wire". According to the lame Isuzu manual this is a power wire for the TOD computer, while if you look here

TOD 50/50 mod for Trooper

Is a scheme that includes a switch that when in ON position sends +12v to the TOD _solenoid_ control wire (the yellow one), that makes the TOD clutch to be completely engaged. It is obvious that grounding of this wire will make the TOD clutch to be completely disengaged.

Please tell me where I'm wrong... :cool:

What if somebody else tried already?

This is why we communicate, it is probaly one of the main concepts of civilization -- in the old days it was: "Do not eat those mushrums", now it is "Do not touch that wire"...

:D

I have all the service manuals and Electrical Wiring Diagram for 2000 Trooper. Let me know if you want any scans. (Helm apparently doesn't own a CD burner... CD has been out of stock for months; I had to buy the printed version).

Nate

I think that it is a great idea. The Trooper 2wd/4wd switch has to do something to tell the TOD computer that it shouldn't engage the clutch pack. If someone with the Trooper book could scan or look at the wiring diagram and let us know what that switch connects to, it would be a start.

We can ignore the part about the vacuum disconnect on the front axle, at least until someone swaps axle housings.

-Tad

Quote:

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Originally posted by Nazrat
I think that it is a great idea. The Trooper 2wd/4wd switch has to do something to tell the TOD computer that it shouldn't engage the clutch pack. If someone with the Trooper book could scan or look at the wiring diagram and let us know what that switch connects to, it would be a start.

We can ignore the part about the vacuum disconnect on the front axle, at least until someone swaps axle housings.

-Tad

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Well... I have the 2000 and 2001 Isuzu manual, it incudes Trooper and VX. I didn't check on the live TOD computers, but it looks like Trooper's TOD computer got an extra one connection for the switch, and it also got extra connections to send commands to the vaccum-electric devices (that are not installed on VX) to perform the disconnect...

Quote:

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Originally posted by nater
I have all the service manuals and Electrical Wiring Diagram for 2000 Trooper.
...
Nate

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Thanks, I think it's the same thing I got.

I wonder if anybody got a Wiring Diagram for VX?

The CD on Tone's site has the VX diagram in it. It would be easiest for someone with the Trooper diagram to compare the two, but if someone can provide me with a copy of the Trooper schematic, I will.


-Tad

Michael, the manuals for Trooper and Vehicross are indeed seperate. If yours are one book for both, they must be from chilton or haynes. I have the REAL manual from Isuzu. Let me know if you would like any pages from it.

Nate

Quote:

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Originally posted by nater
Michael, the manuals for Trooper and Vehicross are indeed seperate. If yours are one book for both, they must be from chilton or haynes. I have the REAL manual from Isuzu. Let me know if you would like any pages from it.

Nate

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I have a huge set of .pda files, packaged together... It is from Isuzu. It is called "Isuzu <something> Repair Manual" I'll try to extract the relevant pages into separate pdfs and then I'll post them here.

The wire we have interrupted (LB) is voltage to the clutch solenoid not the TOD ECU - check your diagram. I have tried suppling 12v to engage the solenoid completely with no luck. I give up - posts deleted. Good luck.

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Originally posted by Tone
Use the search feature Sir Micheal - learn how to fish instead of asking to be fed. You’re new around here, might want to try stuff and THEN report back with all your ducks in a row. BTW, the wire we have interrupted (LB) is voltage to the clutch solenoid not the TOD ECU - check your diagram. I have tried suppling 12v to engage the solenoid completely with no luck.

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Well... search for "TOD disconnect" and "TOD switch" doesnt return any good results... So I looked at the manual I got, asked my friends, and finally posted a new thread, hoping that somebody will either refer me to the right how-to article, either will give enough details about the mod...

Thank you,
Michael

Quote:

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Originally posted by Michael S.
Well... search for "TOD disconnect" and "TOD switch" doesnt return any good results... So I looked at the manual I got, asked my friends, and finally posted a new thread, hoping that somebody will either refer me to the right how-to article, either will give enough details about the mod...

Thank you,
Michael

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Michael - you're right, THE purpose of this board is to help each other and bounce ideas back and forth (2+ heads are better than one) - looks to me like you did your homework, you were just looking for feedback. Although I haven't had time to tackle this project yet, it is on my list of mods I want to make. I have been watching all posts regarding this matter with much interest, and there seems to be a lot of different things being said. I can't remember anyone saying that it worked exactly as it should, and then following thru with information on how to do it - except for the Trooper guy. No one on a VX has said theirs works as it should and then has told us what exactly they did that I recall. Someone chime in if I'm mistaken. Tone - does yours work without turning on the "check TOD" light? If so, share your success with the rest of us, please.

Maybe I'm confused here, but is the question whether or not you can install a TOD disconnect switch? If so, the answer is yes, with less than a half hour of work. I've had mine in for a few months now with no problems. I like the way RWD handles on pavement and you save a little gas 'cause you can coast without the engine braking kicking in.

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Originally posted by Spy Hunter
Maybe I'm confused here, but is the question whether or not you can install a TOD disconnect switch? If so, the answer is yes, with less than a half hour of work. I've had mine in for a few months now with no problems. I like the way RWD handles on pavement and you save a little gas 'cause you can coast without the engine braking kicking in.

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Are you operating without the check TOD light on? Post some directions - share the wealth, that's the value of this site!

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Originally posted by Raque Thomas
Are you operating without the check TOD light on? Post some directions - share the wealth, that's the value of this site!

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didnt it have to do with puttin a load on the wire so it thinks its still connected to the silinoid(sp?)?
________
Web shows

There are 3 possible modes for VX:

1. Regular TOD mode.
2. TOD Off, Clutch Solenoid ON (50/50 HI)
3. TOD Off, Clutch Solenoid OFF (2WD HI).

To prevent Check TOD error, the TOD control unit must be connected to the dummy load.
Provided diagram shows how to do this.

You need two switches. One for TOD ON-OFF, and second to
switch between 50/50 HI or 2WD HI.


Relay 1 used for locking Clutch ON-OFF Switch in TOD ON mode.
Relay 2 used to connect Clutch Solenoid (In TOD ON mode) or Dummy load (in TOD OFF mode) to the TOD Control Unit.







http://members.cox.net/vovkus/Pictures/forum/TODVX.JPG

vovkus,

Thank you!

The scheme looks like the right one... ;)

I have a questions and one addition though:

1. I see a 30A fuse here -- isn't this little too much? If I recall it correctly the Trooper guys are putting 10A for their 50/50 mod.

2. The wire to use is an LB wire coming out from the connector C-44 pin No 4. ( I was wrong wen said that it is a Y(ellow) wire! ).

http://s87087280.onlinehome.us/tod1.gif
http://s87087280.onlinehome.us/tod2.gif

The above screenshots are taken from the Isuzu VehiCROSS 2001 Repair Manual.

I'd love to see the same screenshots or paper pages describing the Trooper TOD computer. This is entirely speculation, but the Trooper could use the 4-hi switch as the "TOD on" signal. I wouldn't try it until someone comes up with the Trooper diagram however.

-Tad

This is all great information, but isn't the front drivetrain still going to be turning all the time, negating and mpg improvement?

That is, unless you install manual hubs...

Hey, why does it say I only have 1 post? I have a few more than that here FWIW.

Quote:

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Originally posted by Nazrat
I'd love to see the same screenshots or paper pages describing the Trooper TOD computer.
...
-Tad

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Here you go:

THIS IS IMAGES FROM ISUZU WOKSHOP MANUAL FOR TROOPER !TROOPER! 2001


http://s87087280.onlinehome.us/tod3_trooper.gif
This is the solenoid control circuit.




http://s87087280.onlinehome.us/tod4_trooper.gif
The 4WD Auto switch connection.





http://s87087280.onlinehome.us/tod5_trooper.gif
And this is something that VX doesnt have -- VSV (Vaccum S??? Valve) ...


Sorry for lack of details and lousy pics -- have to work, you know :)

--
Michael

Looks like pin 30 in connector B-48 is the TOD switch input to the TOD computer. According to the CD that I'm looking at about the VX the pins and connectors are entirely different. So much for the "Easy Way"

-Tad

Quote:

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Originally posted by Michael S.
Here you go:

And this is something that VX doesnt have -- VSV (Vaccum S??? Valve) ...


Sorry for lack of details and lousy pics -- have to work, you know :)

--
Michael

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VSV = Vacuum Switching Valve - this is what engages the axle-disconnect in the front axle.

-Tad

Sweet moses! You can do all that fun stuff if you want 4HI, but if you just want 2WD, cut the light blue wire going into the box under the passenger seat and install a 3-pole switch with an LED or light, bingo 2WD

I made a mistake on the
Diagram

1. Use 10 AMP fuse instead of 30 AMP.
2. The "hot" wires (+12V) of all switches need to be connected to the +12 V source controlled by ignition switch.
Sorry about that.

Mmm would it be of any help if I try to get the Japanese VX's work manual...we also have TOD and 2 hi, like the trooper...:D

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Originally posted by dutchie
Mmm would it be of any help if I try to get the Japanese VX's work manual...we also have TOD and 2 hi, like the trooper...:D

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Yes! I'll buy you a beer next time that you are in town if you can come up with that :)

-Tad

Quote:

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Originally Posted by vovkus

There are 3 possible modes for VX:

1. Regular TOD mode.
2. TOD Off, Clutch Solenoid ON (50/50 HI)
3. TOD Off, Clutch Solenoid OFF (2WD HI).

To prevent Check TOD error, the TOD control unit must be connected to the dummy load.
Provided diagram shows how to do this.

You need two switches. One for TOD ON-OFF, and second to
switch between 50/50 HI or 2WD HI.


Relay 1 used for locking Clutch ON-OFF Switch in TOD ON mode.
Relay 2 used to connect Clutch Solenoid (In TOD ON mode) or Dummy load (in TOD OFF mode) to the TOD Control Unit.

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Heh. So I couldn't resist trying this anyway. Fun to build, but no, it doesn't work as Tone said it wouldn't.

It does work as a TOD disconnect without the Check TOD light, but feeding 12V directly to the clutch solenoid (both switches on) did not get me 50/50.

Oh well.

-Daver