03 4x4 issues

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jose6326

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about 2 years ago i had issues with the 4x4 selector buttons not working.
luckily, on this site i found out it was a cold solder issue and i was able to repair the problem.


i always have it set to 2-hi when i drive
for the past several months when i start it up it randomly sets to auto, or 4 low.

sometimes i can go days and it will stay on 2-hi and sometimes it will select a different 4x4 setting.

is this normal?


my main concern is that one day i started it up, drove off and realized it randomly selected 4hi since i can feel the heavy load while driving.

so i pulled over put it in neutral and selected 2hi.
when i did this i heard and felt to loud clunking or thumping sounds which i think came from the rear end.

are the gears going bad?

what should i look for or open up to inspect?
 

Big Mama

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Have you heard it since? If you repeat the same process does it do it each time?
 
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jose6326

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i will set it to 4hi or 4lo and will see if it does it again.

i didn't want to try it because i was afraid something might break and then i get stranded
 

Big Mama

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I’d just try in your driveway but if you think something broke remove the rear cover and look for anything obvious. You can also jack up the rear end in put it in neutral and spin the tires by hand to see which wheels turn.
 

Doubeleive

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Most likely it is a bad switch if it is changing on its own or doing random lights or no lights when you didn't hit the button. if you change it out use a oem one
 

Fless

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You can remove and ohm the switch to make sure that each button press sends the right signal (by resistance value) to the encoder motor. Let me know if you need the ohm values and which terminals to check on the switch. I'd recommend checking the voltage, too, that the switch is getting from the Transfer Case Control Module.

If it's not the dash switch, it's likely the encoder motor on the transfer case.

Do you know which transfer case you have?
 

Fless

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for the past several months when i start it up it randomly sets to auto, or 4 low.

sometimes i can go days and it will stay on 2-hi and sometimes it will select a different 4x4 setting.

is this normal?

No, that's not normal for it to change by itself.

my main concern is that one day i started it up, drove off and realized it randomly selected 4hi since i can feel the heavy load while driving.

so i pulled over put it in neutral and selected 2hi.
when i did this i heard and felt to loud clunking or thumping sounds which i think came from the rear end.

are the gears going bad?

what should i look for or open up to inspect?

There will be a "clunk" when changing into and out of 4hi. That's normal, and it's the sound of the transfer case switching modes.
 
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jose6326

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You can remove and ohm the switch to make sure that each button press sends the right signal (by resistance value) to the encoder motor. Let me know if you need the ohm values and which terminals to check on the switch. I'd recommend checking the voltage, too, that the switch is getting from the Transfer Case Control Module.

If it's not the dash switch, it's likely the encoder motor on the transfer case.

Do you know which transfer case you have?

please provide the ohm values


how difficult is it to change the encoder motor?
i will check youtube to see if there is a vid.

how do i find out what transfer case i have?
is there some type stamping on the case?
 

Fless

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please provide the ohm values


how difficult is it to change the encoder motor?
i will check youtube to see if there is a vid.

how do i find out what transfer case i have?
is there some type stamping on the case?

I'll post up some instructions for testing the switch once I get home from work.

Look in the glove box for the RPO sticker. There should be a bunch of 3-digit codes, which tell the build setup. Look for one that starts with "NP..." and get that. If that's the Auto 4x4, it will most likely be NP8; that's the NVG246. I think the code for the other TC is NP1 or NP4, IIRC (Borg Warner?). They take different encoder motors.

The encoder motors aren't particularly difficult to replace, but for the NVG246 you have to remove the front prop shaft (driveshaft) from the TC and the front differential. Typically a replacement encoder motor would require the TC to be put in neutral, but I've seen them come other ways and the instructions should state which position the new motor is set for.
 

Fless

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@jose6326,

Here’s a decent article with some troubleshooting. See the third page of the linked PDF or below for the ohm values. About the voltage measurement: if you measure the voltage from the ATCM also note that the full article is for a different encoder motor system / connectors and references 8v, not 5v. Your system could be either 8v or 5v, I’m not sure when they changed it, but it’s probably 5v. I'd like to know which one yours is.
http://www.atraonline.com/gears/2006/2006-08/2006_08_08.pdf

Switch measurement procedure here, starting at about 2:10 into it.

Auto4WD = 61.7-68.1 ohms
4HI = 656-760 ohms
2HI = 1.50-1.53 K ohms
4LO = 2.32-2.37 K ohms
Neutral = 1.015-1.035 K ohms


There are a few videos out there on YouTube on how to replace the encoder motor, here's one:
If you're going to change your encoder motor, I would recommend setting your 4wd system into the mode position that the new encoder comes in. Some come with the TC position as neutral, others come in 2hi. Some of them don't recommend moving the encoder motor (with the dash switch) while it's not attached to the TC.

Hope that helps.
 

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