Hey guys,
I have since converted the vac actuator to a locking cable setup for the front axle. Now, in PARK, no engagement of 4hi or lo. In NEUTRAL, no 4hi or lo, no lights on 2-button. In OD/D/2/1, no 4hi or lo, no lights on 2button. In REVERSE however, 4hi: lights blink, go out. 4lo: lights blink,
TCCM powers up, encoder motor powers up, sometimes 4lo light stays on,
other times not. In one instance, i hit 4lo again to go back to 2WD, started backing up and the sound from the TCASE sounded like a thru the truck in PARK
at 30MPH, tried backing up again...slowly... and both 4hi and lo lights were on and the truck seemed to be in 2WD again, turns freely, more power in OD. I havent jacked up the front yet, but could this be a problem with the encoder motor, as in the NV233 transfer case / encoding motor switch thread?, or does the fact that anything only happens when in reverse setoff alarms to anybody? Any help appreciated

 

Sounds like an encoder fault. You could monitor the encoder channels to see if they switch appropriately when you attempt a shift...

 

According to the NV233 transfer case / encoding motor switch thread, any encoder fault can be read through the ALDL, but i dont seem to have a J terminal to check for a code. My SES light seems to cycle on and off almost rythmically, ill check for any new motor-related codes, but how would i pull any encoder fault without term J? Can the encoder circuit be monitored through the 2button switch? Than again

 

No, you have to monitor the output by back probing the appropriate wires at the TCCM or at the encoder motor itself.

 

Last two,
Would an encoder fault cause the TCCM to engage the encoder motor when in reverse only, or does that appear to be another issue? Is there a specific link to the 4WD sequence of operation (switch sends signal to TCCM, TCCM to encoder, so on and so on)? Thanks for the help again

 

It may just be easier to shift when in reverse skipping over the problem point in the encoder fast enough that the TCCM does not react to the problem.

What kind of link are you looking for? The TCCM unlocks the encoder motor then pulses the motor to move it while monitoring the position of the motor until certain criteria are met (encoder channel output in a specific sequence).

The thread started by error_401 in the Tech Article (DIY) section and followed up to by me have these details hammered out quite well.

 

I had performed more serches and found the schematics from rsgear.com,
very helpful!!! I pulled the front axle indicator switch and noticed the cable inside the cable assembly in the front axle. It appears that the cable is pulling enough to engage the front axle, but not enough to complete the indicator switch. A metal sleeve around the cable in the cable assembly only travels about 1/4 inch, not far enough to push in the ball on the back of the indicator switch, hense no light on the 2button. Is there a way to adjust the cable in the cable assembly at the front axle, or is this factory set? I can only assume the cable can have some stretch over time? Thans again

 

It may be that the cable is restricted somehow and may only require some lubrication and working it back and forth to free it back up. The vacuum actuator will pull the cable more than enough provided the resistance is not too high. There also may be a problem with the vacuum supply to the actuator not being strong enough.

 

Update: I was able to adjust the cable pull distance in the front axle shift cable assembly to allow the cable to close the front axle indicator switch. Some back-and-forth meneuvering of the cable started to free it up. Now in some instances, both the 4HI and 4LO indicator lights will be on at the same time. Could this be the encoder sticking between 2 settings, causing the TCCM to complete both circuits on the 2-button switch? When the truck is in 4LO, the 2button switch lights are out, would this be the dreaded "rail-to-rail" issue? Sorry for so much, i seem to open Pandora's Box everytime i touch something anymore