Ok as the title said, I have a WTF problem. Also, like the title said, heres what ahs been done...
What I Have: NP 236 TC, 4 Button (Auto 4, 2 Hi, 4 Hi, 4 Lo)

The Problem: No 4 Hi or 4 Lo. Auto 4 works just fine. i can hear it lock in when ideling. i can feel it drain power (slightly) when moving. 4 Hi blinks for about 10 seconds and goes to auto 4. 4 lo blinks for a few seconds then (1 out of 5) goes to auto 4 or (4 out of 5) trips the service 4wd light and kills all lights on the buttons.
Also when attempting 4 hi or 4 lo, I can hear the TC working, but no positive "drop in" lock sound.

Attempted Solutions: Driving it into a pond--> Didn't help.
Pulled battery and plate and checked vacuum accuator--> No rips, tears, corrosion, leaks.
Followed vacuum lines--> All are in good order and no cuts tears, rips, or holes.
Replaced 4 button selector (used)--> No Dice.
Replaced TCCM (new)--> no dice.
Attached new encoder motor--> No dice.
With encoder off, unlocked and attempted to move through the settings--> TC is not frozen, moves under pressure.
Checked and cleaned electrical connectors/wires--> Good contacts. No dice.
Checked Fluid level--> At/over top check plug. (leaks when loosened).
Checked Fuses--> Good to go.

Where I am Now: With my head in my hands weeping patheticly. I have been sifting through 4 button problems for a little while now. I have not seen anything like what I have described, that has not been corrected by one of the listed cures. I do not have a tech 2 tool to talk to my TC. Is there any chance that my new TCCm needs a 'fill'? Like someone needs to plug into to it and tell it WTF it needs to do or something else equaly lame, but easy to fix?
I am open to any and all suggestions, and am willing to try anything up to and including installing a new TC (as a last resort). I do not want to throw parts at this problem (a useful $100 for an uneeded TCCM is not my idea of progress).
thanks all !

 

Did you get any codes from the TCCM when accessed via the Tech2?

 

I dont have a tech 2 to chat with the TCCM. that would make this thing WAY too easy. unless there is a place like autozone that lets you plug a tech 2 in... ?

 

Ah, read too quickly. Thought you said you had one. Well, accessing the TCCM will give you an indication of why it cannot complete the shift. Rather than just tossing parts at it.

*EDIT* - The post below should give you the resistance values for the switch:
4x4 Light consistent blink while engaged

You can also try energizing the vacuum solenoid valve on the firewall to see if it actually opens allowing the front axle to engage.

 

Check. Will crack open the assigned reading, and take a stab at diagnosing from the solenoid. Thanks for the leads

 

**UPDATE**
Solenoid --> Getting power at connector.
Tried the battery trick --> No change.
Attempted 4 Lo to trip Service 4WD Light (no lights at button at that point) --> Nothing works.
Checked TCCM (the new one) --> Power in, NO POWER OUT.
Put in 2nd New TCCM and new Button Set --> Buttons now Lit. Power out from TCCM but threw Codes. (see below) No functional TC shifting though.

With TCEM disconnected, moving through setting manually I can only Find 4Hi and 4Lo. WTF? It is possible that 4hi = 2hi, just nothing kicked in at the differential, BUT that doesn't explain the lack of a neutral setting. Is it possible I have an Incorrect TC under there (i.e. an all time 4wd TC from a 92 or something?) Would explain why the TCCM can't communicate... *shrug*

How would I ID the TC?

What is the normal range of control at the TC? (From front working to rear manually)

Any help at all is appreciated (and needed!)



Techtron II codes : 323 and 387

 

C0323 - Transfer Case Lock Circuit Low
C0387 - Unable to complete shift

You have a problem with the encoder motor lock. Here is how a shift happens with this transfer case:

1. You push the desired shift selection
2. TCCM checks the encoder to make sure that it is not currently in that position and determines which direction (if any) it needs to move in.
3. TCCM unlocks the shift motor.
4. TCCM commands the shift motor to turn the shift sector shaft while monitoring the signals from the encoder.
5. Once the TCCM sees the encoder at the proper position, it will stop the motor.
6. TCCM locks the motor back up.
7. TCCM lights the appropriate light on the switch in the dash to indicate that the shift has been completed.
8. IF you have selected 4HI or 4LO, the TCCM will also open up the vacuum solenoid on the firewall.

I doubt you have an older transfer case in there. It should say NV236 or NP236 on the aluminum disk mounted to the rear of the transfer case.

The reason that the replacement TCCM was able to do marginally more was likely due to it not knowing about previous faults. Once a TCCM sets hard codes like the ones you have, it will halt any attempts to shift.

Are you sure you got the right encoder motor? Have you checked all of the fuses (specifically the ATC fuse)?

I am trying to find the schematic of how the NV236 sector shaft rotation relates to which gear you are in.

 

Kyle, thanks for going to bat on this one. I am glad that I have a ringer like you to lean on. I will try out a new encoder motor, just in case. Also I will double tap the fuses (they were checked a while back). I am reading up on the fault links you provided (thanks BTW) and will bash my head against the wall a little more on this thing.

Wish me luck!

 

No problem!

Concentrate on the lock control code. If the encoder motor does not unlock, it cannot complete the shift. Test continuity from the connector on the TCCM to the connector on the encoder motor.

 

**Update** Struggling wo find the proper setting on the TC to get my TCEM installed. they are about to shut the lights off on me and I'm losing my brain on this. It's been going for a while now with no progress. Is there a neutral detent that i can manually set the TC to for the purpose of install? Does anyone know the shift order of manually going through the TC setting (i.e. furthest forward is 4 hi than 2 hi then nuetral then 4 lo from front to back) i cant get this damn thing to marry up with the TCEM because I dont know what the hell setting my TC is in. When I pulled the old TCEM it was under pressure (binding a little) and the tc popped forward. since then, I have manually worked through it and have no idea WTF setting im at
Help anyone?