TOD and no rear driveshaft....

[Triathlete]

After thinking a bit I have come to the conclusion that your front drive only experiment means moot. And here is why...
When in 4hi the front end was getting 20% power...obvouosly not enough to pull the VX. All wheels would have been turning equally at the same rate.
In 4lo there should not be any jerking since in 4lo the transfer case is mechanically split 50/50 and takes TOD out of the equation.

[Marlin]

After thinking a bit I have come to the conclusion that your front drive only experiment means moot. And here is why...
When in 4hi the front end was getting 20% power...obvouosly not enough to pull the VX. All wheels would have been turning equally at the same rate.
In 4lo there should not be any jerking since in 4lo the transfer case is mechanically split 50/50 and takes TOD out of the equation.

I agree, except that its not moot. TOD should sense the rear wheels slipping (no drive shaft, the puter thinks it is, so it senses slipping, no different than it would be on snow) and subsequently sends power to the front. That was the problem, it doesn't take the slipping input and then transfer power at a rate fast enough to make it doable,hence the jerky responses, then it seemed to reset and start the process over, giving it that bouncy jerky effect. Having said that, imagine the effects of the delay on snow or ice.

If I had to drive this way, it would be in 4low only, to remove TOD from the picture and have the straight mechanical drive engaged.

[Triathlete]

I agree, except that its not moot. TOD should sense the rear wheels slipping (no drive shaft, the puter thinks it is, so it senses slipping, no different than it would be on snow) and subsequently sends power to the front. That was the problem, it doesn't take the slipping input and then transfer power at a rate fast enough to make it doable,hence the jerky responses, then it seemed to reset and start the process over, giving it that bouncy jerky effect. Having said that, imagine the effects of the delay on snow or ice.

If I had to drive this way, it would be in 4low only, to remove TOD from the picture and have the straight mechanical drive engaged.

Where does the tod computer get its wheel speed input from? Maybe I am missing something but, if the VX is moving, with or without a driveshaft all four tires are spinning at the same rate so why would the tod send power to the front? Sounds like it is doing what it is supposed to.

[Marlin]

Where does the tod computer get its wheel speed input from? Maybe I am missing something but, if the VX is moving, with or without a driveshaft all four tires are spinning at the same rate so why would the tod send power to the front? Sounds like it is doing what it is supposed to.

With no driveshaft,the vehicle is not moving at the calculated speed that it should be. I am not sure where all the sensors are, but I know there are front and rear. It basis the wheel speed off of the calculated speed based on RPM and gear. At 2000 RPMs, I was not moving, so it transferred power to the front, assuming the rear wheels were spinning out for some reason (rear tires on ice, spinning at 20mph, front tires only spinning at 5mph, therefore shifts power to front)? I don't know what it uses as a reference for the speed.
All I am saying, if the rear tires were on ice, as simulated by removing the drive shaft, I would think the power transfer to the front should be smooth.

I learned to drive in a 1978 volvo wagon, rwd, in Ohio. I prefer RWD cars in the snow, and anticipate the fish tale and prefer to drive based on my own predicted path, not a path that is determined by some computer.

[Marlin]

I got it! The TOD sensors are in the transfer case! When the drive shaft begins to spin faster than the prop shaft,that is considered wheel slip in the rear and power is transferred to the front. That is why TOD goes crazy. It sees the rear shaft spinning fast(even thought the shaft isn't there, the sensor is in the transfer case), the prop shaft isn't spinning at all. It then shifts power to the front, giving me the jerking as the clutch tries to engage at a few thousand RPMS and a higher gear, which gives the tranny a bitch of a workout.

One more experiment. Disengage my hubs, no wheels are connected to the driveline. Then I can watch the TOD lights disco it up on the dash without fear of hurting something.

[nfpgasmask]

All I am saying, if the rear tires were on ice, as simulated by removing the drive shaft, I would think the power transfer to the front should be smooth.

I see what you are saying here. However, in defense of the TOD, I think your "experiment" is only applicable in extreme situations, IE, rear end sitting in soup or on a perfect sheet of ice. Normally, the rear end is getting some traction, even if it is minimal, so that when the slipping begins in the rear, the TOD kicks on and send power to the front, making the TOD seem to operate smooth, more-or-less. Now, with the rear drive shaft out, you are going to experience a completely NON factory reaction to your experiment, so jerky stop and go action does not seem wrong to me, just natural for the TOD. Meaning, the TOD would rarely kick on from a DEAD STOP, as there is typically some forward momentum happening when it kicks on normally. Know what I mean?

All that aside, I see what you are saying about wanting a "normal" 4WD transfer case, but then I have no choice to go back and tell you that you bought the wrong vehicle to begin with.

I personally don't understand some folks extreme desire to turn the VX into something that it is not. The VX was not meant to be lifted 4"s, it was not meant to have a SAS, it was not meant to have a winch bumper up front, it was not meant to run 35"s, it was not meant to etc etc etc. However there are always people trying to make it do things it wasn't meant to do, and then they get discouraged or turned off or upset about it when these mods don't work out so much. And you know my answer to all of that (buy a Jeep, cough, cough). But again, all the power to ya.

On the contrary, got my VX front end back together, and removed the ABS speed sensors, tone rings, ABS fuse and the wiring, and she runs just fine!!

Bart

[MSHardeman]

The VX wasn't meant to run without ABS.....

Sorry Bart, had to do it.

Now, sort of, back on topic; from my understanding of the TOD system, it's not supposed to send sustained power to the front wheels. It's only supposed to throw power forward in little spurts to get everything moving again. It's not like an all wheel drive system in an Audi. I know the TOD has saved my butt many times in the Colorado snow and ice. I've tried to get her sideways before, but the little power blips to the front end just straighten her right back out.

[nfpgasmask]

The VX wasn't meant to run without ABS.....

Sorry Bart, had to do it.

I know, I know, that's why I said, "On the contrary". My VX isn't 100% stock either, I just try to keep it clean and simple. And yeah, I have TRIED VERY HARD to do donuts in the snow and I can't. Now, the Trooper can spin like a merry-go-round in the snow.

Bart

[Marlin]

All that aside, I see what you are saying about wanting a "normal" 4WD transfer case, but then I have no choice to go back and tell you that you bought the wrong vehicle to begin with.

I personally don't understand some folks extreme desire to turn the VX into something that it is not. The VX was not meant to be lifted 4"s, it was not meant to have a SAS, it was not meant to have a winch bumper up front, it was not meant to run 35"s, it was not meant to etc etc etc. However there are always people trying to make it do things it wasn't meant to do, and then they get discouraged or turned off or upset about it when these mods don't work out so much. And you know my answer to all of that (buy a Jeep, cough, cough). But again, all the power to ya.
Bart

By that logic, no one would ever have a modded street legal offroad vehicle as NO vehicle was meant to do these things.

Anyway, the next step in the experiment would be to do the TOD mod where I can adjust power manually via rheostat. I would think that the TOD software would have a feedback loop built into it to prevent the surging/thunking effect.

No worries, the shaft is back in, and she is back to normal.

On a side note, I figured out what my squeaking sound was!! The rear lower link mounts have the edges bent over just enough that the moving portion rubs on the fixed portion. It is always loudest in reverse, which generally means I am riding my brakes a bit when backing out of the driveway, which compresses the rear suspension backwards and at an angle, also the engine is quiet. That makes the squeak seem louder as the vehicle tends to bounce at an angle. Just need to bend that steel back a bit....

[nfpgasmask]

By that logic, no one would ever have a modded street legal offroad vehicle as NO vehicle was meant to do these things.

I dunno, I think Jeeps in general are built knowing that there is a huge offroad aftermarket for them. True, once you start modding in any way, you are doing something to a vehicle that was not originally intended, but that isn't my point. I'm not knocking anyone's attempt to turn their VX into something that it was not meant to be, I am just always confused when people do this and then get disappointed/discouraged/upset when the end result isn't so great or still doesn't do what they want it to. It's like taking a boat and turning it into a car. Sure, it can be done, but it might not look so good, and it might not handle so good, etc, etc, because after all, it's a boat. But, if you have the skill, drive and desire, by all means turn that boat into a car!

Bart