Stuck in 4hi-loc!

[Scarsman]

Not sure what the deal is, and I haven't had time to even start looking into it yet, but I found today that Big Blue is stuck in hi-loc. The light says it's in hi, but driving it says it's in loc!

A few weeks ago I had a couple times where I noticed the red neutral light was on while driving down the road. Shifted it to low and back and then hi would light again. Did that a few times and then was normal again.

Shifts to low and back just fine right now, and the locker works. Transfer case just won't unlock in hi even though the light comes on indicating it thinks it's unlocked.

 

[Zach]

Has service 4wd come up on the DIC at all? Any codes? Possible encoder motor going out.

 

[Scarsman]

Nope, no codes or service 4x4 system notice. I'm guessing it'll end up being the encoder motor. I checked Rockauto and they have reman ones for $140.

 

[Big2dabank]

I had something similar happened several months ago, except I couldn't get out of 4 low lock. I left the truck in neutral, turned off the ignition and started the truck back up and immediately hit 4 hi. It flashed at me for a few seconds and then clunck, it shifted into 4 hi . Not sure why it work or what was the deal but that work for me. I attributed it to my ABS woes, because it wasn't long after that that my EBCM went out. Once the EBCM was out I couldn't do crap with the transfer case until I replaced the EBCM module. I'm sure it's not remotely related to your issue but what the hell, you never know.


Sent from my iPhone using Tapatalk

 

[twinmill28]

Mines been showing the red light most of the time I drive now but it's in 4hi. I stopped yesterday and tried to get it to shift to the other two and it blinked then went red again and stayed in 4 hi but didn't display any lights (red or yellow). Once I realized how dumb it was for me to have pulled off the road with the chances of it getting locked in 4 lo I drove home and tried again in the driveway after restarting it. Once I restarted and shifted it blinked and went through the modes no problem so I set it back to 4 hi and shut it off.
I really don't feel like screwing with this when I still haven't figured out what my air suspension is doing---it feels like I'm running through how many trouble warnings I can get to show up on the dash!

 

[Zach]

When my encoder motor was on its way out, initially turning the truck off and then back on, it would reset. Then, wouldn't cycle through. Just replaced it and all good

 

[twinmill28]

Hey check you messages Zach, I sent a question about the air susp.----

I'll put replacing encoder motor on my evergrowing never-ending list of **** I need to fix

 

[Zach]

Hey check you messages Zach, I sent a question about the air susp.----

I'll put replacing encoder motor on my evergrowing never-ending list of **** I need to fix

Replied

 

[5gn-h3t]

I had the same problem. No codes or anything. It would intermittently get stuck in 4-HI lock with the dash light saying 4-HI. If I shifted it back and forth, it would eventually go into the true 4-Hi. I replaced the shift motor and everything works fine now.

 

[mudbug]

Mine was doing the red neutral light but the h2 still drove in 4hi, then the battery died. I changed the battery and the t-case shifter started working correctly.

 

[Scarsman]

Sounds like it's likely going to be the encoder motor from all of your experiences. Funny thing is yesterday it just went into hi just fine. Going to avoid using loc until I get a motor and have time to put it in.

Does anyone know if there are any sensors inside the transfer case to read what range or setting it is in, or does it get all that info from the encoder motor? It's a crazy thought, but I was thinking of looking while the motor is off to see if there could be a way to make a mechanical shifting device to replace the motor. Then mount the motor somewhere out of the way and you could still push the buttons and the motor would move and give the computers the right signals to keep them happy.

I don't know. Just a crazy thought having never had the motor off or seen what's in there yet.

 

[ADOR]

Mine will sometimes start of RED light (neutral). When I start driving, I just press the 4HI, then the light will stay on 4HI. There are also times when I am driving, then shift to reverse, the RED light will turn on again. This keeps on happening lightly. What does the Encoder Motor actually do? Is it OK to keep driving with this LIGHT problem? Or is it a must to replace that part?

 

[Zach]

The encoder motor is the thing that shifts through the different ranges, 4hi lock and 4low. It's more of an issue wheeling, on the street, not so much.

 

[Scarsman]

The encoder motor is the thing that shifts through the different ranges, 4hi lock and 4low. It's more of an issue wheeling, on the street, not so much.

Unless it sticks you in lock mode all on its own! [emoji35]

 

[4speedfunk]

Scars....No. There are no sensors inside the T-case (except the VSS). The encoder does not cycle or operate on its own, as you drive around...it's merely a substitute for a lever or cable.
The variable torque-splitting feature (in 4Hi-street) is a 100% mechanical device. No electronics. It's basically a small sun/planetary differential assembly on the input shaft.
Yes. You can remove the motor and cycle the modes by hand (pliers). Also there is a company making a bolt-on knob to replace the motor. Seems like a strange idea since you have to crawl under the truck to change modes....but whatever.

 

[Scarsman]

Sweet! Good info. Thank you! Yeah, a knob seems a bit odd. I would want to incorporate it to a lever h inside the truck.

Do you have a link or info for that knob? Might be half the work done if I could get one of those and adapt it.

 

[twinmill28]

Scars....No. There are no sensors inside the T-case (except the VSS). The encoder does not cycle or operate on its own, as you drive around...it's merely a substitute for a lever or cable.
The variable torque-splitting feature (in 4Hi-street) is a 100% mechanical device. No electronics. It's basically a small sun/planetary differential assembly on the input shaft.
Yes. You can remove the motor and cycle the modes by hand (pliers). Also there is a company making a bolt-on knob to replace the motor. Seems like a strange idea since you have to crawl under the truck to change modes....but whatever.

This sounds similar to what my buddy was explaining that Fords run a similar setup and is actully the same thing as a power window motor. He did say the Ford setup can be cranked by hand, just as you describe for the HUMMER.