Missing vacuum line

[TheDurk]

I am accepting as a given that the TC is engaging and disengaging as it should. That is, you really have power to the front wheels in 4WD and, when you manage to get the front to disengage in 2WD, you can turn the front propeller shaft by hand. This rules out the actuator and the 2-4 selector switch on the shifter...correct?

I actually think I was wrong about which TC you have. There are two, the VF3AM and the VF2A. I posted the VF2A (which it says is used in M/T and A/T) but does not appear to work with an actuator. I am out of my comfort zone here, as I have a manual. The ADD part is the same, from the VSV's and forward, but the TC's are quite different. I am now thinking you have the VF3AM, but in '99 that had the center diff and the button 2-4. I am pretty sure there was no center diff in '97. That means the '99 VF3AM is different than the '97. So I really don't know how your TC switches are set up or even how many you have. We really need a '97 FSM and wiring manual to be sure what's what, or help from somebody who knows more about this than I do, particularly as regards to the '97 auto with button.

So all I can say for sure is that I think the problem is one of the position switches on the TC, but I don't have enough info about your TC to say which one. Sorry, but that's as far as I can go. Your 4WD computer box does not know the 4WD is disengaged because of a faulty switch, so it doesn't tell the VSV's to switch vacuum from one hose to the other.

 

[etc.]

I am accepting as a given that the TC is engaging and disengaging as it should. That is, you really have power to the front wheels in 4WD and, when you manage to get the front to disengage in 2WD, you can turn the front propeller shaft by hand. This rules out the actuator and the 2-4 selector switch on the shifter...correct?

The transfer case seems to be working good. I have definite power to the front wheels. I couldnt get the propeller to spin by hand with the wheels on the ground prior to switching tubes as noted above. However, not to counterdict you, I have read more than a couple times that its supposed to turn with the trans even in 2wd. But I dont know the correct answer.

I actually think I was wrong about which TC you have. There are two, the VF3AM and the VF2A. I posted the VF2A (which it says is used in M/T and A/T) but does not appear to work with an actuator. I am out of my comfort zone here, as I have a manual. The ADD part is the same, from the VSV's and forward, but the TC's are quite different. I am now thinking you have the VF3AM, but in '99 that had the center diff and the button 2-4. I am pretty sure there was no center diff in '97. That means the '99 VF3AM is different than the '97. So I really don't know how your TC switches are set up or even how many you have. We really need a '97 FSM and wiring manual to be sure what's what, or help from somebody who knows more about this than I do, particularly as regards to the '97 auto with button.

I will try again to open the FSM, but for some reason the .pdf locks up my computer.

So all I can say for sure is that I think the problem is one of the position switches on the TC, but I don't have enough info about your TC to say which one. Sorry, but that's as far as I can go. Your 4WD computer box does not know the 4WD is disengaged because of a faulty switch, so it doesn't tell the VSV's to switch vacuum from one hose to the other

I will pull them on my day off and test them

 

[TheDurk]

However, not to counterdict you, I have read more than a couple times that its supposed to turn with the trans even in 2wd. But I dont know the correct answer.

The front shaft turns by hand in 2WD. I've been greasing the zerks on mine for eleven years. Trust me on this.




I will try again to open the FSM, but for some reason the .pdf locks up my computer.

That FSM is a 2002: multi-mode AWD/4WD, center diff and no vacuum system. It's even more off base than my '99 paper FSM.


I will pull them on my day off and test them

Good luck!

My answers in bold.

 

[etc.]

Today I got the chance to pull the switches. My truck only has the Transfer Neutral and Transfer 4L position switch.

Both switches are working good. I also checked the wiring near the switches and they look good and not broken. I also got the chance to install the switch I had bought (84222-35070).

I was wondering, where is the 4wd fuse is at? I'm missing the fuse panel cover on the DS dash. I checked under the hood, and didnt see it.

I also got the chance to test the resistance of the TC actuator. ~185 ohms at #2 and #3. Tomorrow I will have to check the resistance using #2 or #3 and the body.

 

[etc.]

I have 42.2 volts at each of the VSV and the TC actuator engages and disengages when hot wired.

The VSVs click when hot wired. I pulled the 4x4 sensor and its good.

 

[etc.]

No body? not even the 4x4 fuse location?