TOD 4wd high idea

[bobmumgaard]

I recently bought a VX and am new to this forum (which is great for such a niche vehicle by the way) and would love to have the option for full time 4wd for our nebraska snow falls.
I researched the different options and found alot about tod disconnect which sounds like it works and would be what i was looking for.
However, all the information i found on this and trooper sites solves the problem by supply power to the tod clutch to get it to lock up. This works and all but has anyone thought about another way.
Couldn't we trick the tod into thinking the transfer case is in 4 low without the case actually being there? This would lock the clutch and show correctly in the tod display. There has to be some sort of switch or sensor to trick to do this.

Any ideas, or perceviable problems, or has someone already tried this?

[MZ-N10]

someone siad something about it....try to search.

[SGT.BATGUANO]

I know that when one of the tod sensors (I suspect the rear sensor) gets water infiltration it will kick the front in 100%. I don't remember if this caused 4lo or 4hi condition, or if it also threw a check tod light. At your own peril, you could try disconnecting one of the sensors at a time to see what happens. Just remember the posted fix keeps the tod computer happy, so it's probably the best tried and true method, but if you're willing to experiment, you may find another way to skin this cat.

[mbeach]

Water infiltration caused a 4Hi condition for me on 2 occasions now. It also threw a check TOD light.

It was both frustrating and promising for the reasons mentioned above. I assume that the check TOD light was due to the varying values picked up by the sensor as a result of the water shorting across the contacts.

I think that varying the amount of perceived 'slip' by the rear TOD sensor would be the most elegant solution to the 4Hi option problem. By taking this route, the sensor would determine actual slip conditions while in Auto, but the user would be able to select varying degrees of "false slip" in order to divert power to the front wheels by the preset increments (just like the rally VX that Joe Black described).

I believe that I have seen a circuit (AFAIK it hasn't made it off the drawing board) that did exactly what I am describing. It had 4 options: Auto, Condition 1, Con. 2, Con. 3. Each condition assigned a percentage of torque to the front wheels up to 50% of total.

I have the means and materials to make this work, but I have exactly zero time to do the research. To me, this is the best solution because it allows user 'tunability' as opposed to a simple 2-4 option. It would also display correctly, as the mod would be in place at the sensor rather than between the clutch and the computer.

Flame away if it's worth it...

[Maugan_VX]

I'd be willing to try out a mod where I can dial in the amount of torque for the front end or have TOD figure it out.

However I have a little reluctance to start ripping through wiring of a perfectly fine and functioning VX to do the research necessary.

[SGT.BATGUANO]

It may be a Pulse Width Modulated signal, like the speed signal, which is why no one has come up with a soultion to the top speed limiter of our ecu.

I may be wrong, but I've been under the impression that you can use a dc motor controller on a pwm circuit. So, I'm wondering if one could replace the rheostat or variable resistor on the dc controller board with a 4-position switch and four fixed value resistors.

[mbeach]

four fixed value resistors.

Finding the appropriate values would be the tough part here. I suppose that could be done with a meter and the truck up on a chassis lift -but I wouldn't want to be the guy to try it out.

[mbeach]

The Ford guys (who also use a variant of TOD) seem to be all over this one. Look around on the Explorer forums and you'll see some interesting discussions.

Maugan,
I understand your enthusiasm for the stock TOD, as it is just fine for 99% of VX drivers. I (and others) are of that dissatisfied 1% however. I have issues with a system that is not truly ON DEMAND. When I am driving down a snow covered slope (like my driveway) I DEMAND 4hi -yet I do not get it until a rear wheel slips. By then it could be too late. A fall from the driveway of my new house could be fatal. Therefore, I want -no, I DEMAND control of my drivetrain when I want it.

[VehiGAZ]

I agree with mbeach on the limited value of the VX's TOD system on snow. It kind of works, of course, but I hate the way it kicks in full 4WD for all of a couple tenths of a second, then it's right back to 2WD. When accelerating from a stop on a snow-covered road, it makes for a jerky, skidding run. I'd be happier if it stayed in full 4WD for a few seconds after kicking in, even. I will hopefully do the select-a-TOD-mode modification to the TOD computer wiring before this winter - it will allow me to get the system to stay in 4-High when I want it to. That's how I want to drive on a snow-covered road... in full 4WD-High.

But while I dislike the TOD system's dynamics on snow, I quite like the way it works on dirt and gravel roads. There's a fun one near where I live that I can absolutely FLY down like a pro rally driver with the TOD system doing its thing perfectly.

[Maugan_VX]

mbeach,

I realize the need for true 4hi. I don't see where I said it wasn't a valued addition to our vx's.

Actually, I just said that I would love to be able to have a control on my dash that would dial in the trq to the front. 15%,50%,100% or whatever it is.

Thing is, I don't want to rip apart my vx to figure it out

[psychos2]

bobmumgaard, i believe that when in 4 lo the clutches are not used. shawn

[mbeach]

mbeach,

I realize the need for true 4hi. I don't see where I said it wasn't a valued addition to our vx's.

Actually, I just said that I would love to be able to have a control on my dash that would dial in the trq to the front. 15%,50%,100% or whatever it is.

Thing is, I don't want to rip apart my vx to figure it out

If I had a few more minutes to spare in my day, I'd be glad to tear my VX apart. Like I said, not enough time to make it happen. A TOD control knob would be absolutely awesome (similar to the old Ford RS200 rally cars'). I must make this happen at some point. If I cannot, it'll be a 5-speed + old school T-case swap for me. Since I've quit smoking, my right hand is running out of things to do when I'm driving.

[VehiGAZ]

Someone posted a wiring diagram here for how to modify the inputs & outputs of the TOD controller to allow for a selector switch to be used to decide how the transfer case should operate. From what I remember, it gave you the ability to install a rotary switch that could force the TC into either rear-only, normal TOD, or 4WD-high. That's not quite what some of you are looking for, but it's pretty close.

[VX922]

"Someone posted a wiring diagram here........"

Check my old posts
http://www.vehicross.info/gallery/sh...php?photo=6686

[VehiGAZ]

Not the one I was thinking of - but yours is much better!

Thanks for the re-post, VX922! Now I just gotta find time to do it before the snows come...