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But that is not all...
So I still couldn't get it to go into 4h or 4L. The transfer-case was not shifting in and I wasn't getting any dash indicator lights. I tried many times in park, drive, reverse neutral, foot on brake pedal, while rolling while driving, etc. Cut truck off and on several times. Tapped on shift motor. Nothing I tried would get it to go into 4x4. So with the key on and engine off, I go under hood and jumped the front 4x4 relay (RO1) with a paper clip for a few seconds.
This throws power to the T-Case shift motor in CCW direction which is required to move it from 2H to 4H to 4L. If you listen closely with truck off you will here it run for about 4 seconds until it reaches 4L where it hits a built in stop. Now I crank truck and is definitely in 4L. (Computer is probably unaware because there is no dash light.) But after I did this I cut truck off installed the relay and set selector **** to 4L and re-cranked truck and the 4Low light came on and now I could use the selector to switch back to 4 high and 2 High and all started working again. I test drove it and tried shifting in and out of 4x4 several times to see if it would fail to shift again but it worked every time. This is basically what has me stumped? what is causing it not to shift if the motor works fine and the relay works fine and the switch in the dash seems to work fine. I think it is the computer saying no I'm not going to give you 4x4 because I don't like the position signal I'm getting from the T-case shift Motor...
I read about this elsewhere " How to: Rebuild 4X4 Shift Motor " Not sure I'm allowed to link to it so google it.
Ok so after all this my next find is that my driver-side IWE is staying disengaged even in 4H and 4L... So I check and I'm getting vacuum at it all the time... So next I unplug the soleniod and I am still getting vacuum to it??? So I guess the soleniod is stuck open or leaking vacuum through to it when it shouldn't be. So I will also need a new solenoid...
I would say it ...sense it is in between the relay and the SOTF switch...the IWE solenoid
Yeah I'm thinking this too... but I'ts not shorted out and I can feel it clicking on and off when I apply 12v power to it. But I am going to replace it anyway along with the leaking IWE and then see if it gives me any more trouble.
I still can't believe that with all these issues I ever had 4x4 back in Feb... I guess I was just lucky... cause right now I'm having to pull the vacuum line off of driverside so it will engage to get 4x4... lol.
... and that is not a filter, it is a check valve. I would replaced all of them. $10 on Amazon. Replace the IWE solenoid too, as for dirt to get as far as the check valves it first has to go through the solenoid.
UPDATE:
THE GOOD: I replaced both IWE's and the vacuum solenoid. Both wheels now engage and disengage properly... and I can feel a noticeable difference in power not having the front axle engaged all the time!
THE BAD: Still no 4x4. No lights on dash and no shifty at t-case. Also the solenoid still has power to it and never breaks vacuum to IWE's -thus leaving them disengaged. So it seems that the computer never tries to go into 4x4.
MY FIX: I pull the R01 Relay (Powers t-case shift motor in CCW direction) and hot wire the hot terminal to the shift motor terminal for a few seconds and this will run the t-case motor and result in the t-case shifting all the way into 4Low. However, at this point the computer does not yet realize it is in 4x4 so the solenoid continues to pull vacuum and keep the IWE disengaged So I really only have 2low.
But If I cut the truck off and put the selector switch into 4L and recrank it, the computer discovers that it is in 4Low and then the system works fine. I can go to 2H and back to 4H and 4L numerous times with no problem.
But eventually it will go back to not working again.
CONCLUSION: I probably have a failing 4x4 Shift Motor--- Not the motor itself but the contacts inside that tell the computer what position the t-case shaft is in. I plan to pull it apart and see If I can fix/clean the contacts.
ALTERNATIVELY, I may wire up a push button switch on the dash that will activate the R01 relay. I could then just hold the button in for a few seconds to shift into 4Low. Then I could wire up a kill switch to the solenoid so I could engage the hubs. Add a second push button switch for the RO2 Relay (CW rotation) and I could shift back into 2H and bypass the Computer all together.
Just wouldn't be able to shift on the fly
And No 4H because there is no way of knowing where to stop the shift motor when going between 2H and 4L wouldn't want to stop it partially between gears...
05-14-2015, 11:55 AM
what is causing it not to shift if the motor works fine and the relay works fine and the switch in the dash seems to work fine. I think it is the computer saying no I'm not going to give you 4x4 because I don't like the position signal I'm getting from the T-case shift Motor...
