It has a NVG236/246 Transfer case...I changed the shift motor about 2 years ago...

I usually use it in the rain to see if I have any issues coming in the winter.....

I placed it in auto 4WD, and after about 3 miles the service 4WD light popped on....

I took it out of 4wd and all the lights in the selecter switch went out....made a stop and the lights returned and it tried to shift out but when back to 4HI i left it in Auto to get home....

im going to disconnect the vacuum hose to to disconnect the hubs so im not going on dry pavement...any suggestions

Do not use 4W on dry payment.
let it sit overnight and try it.
Also when shifting out of 4W stop and place trans in neutral or back up.

Does all shift light buttone light up for a bulb check?
To test it you will need a Transfer case capable scanner.
Is front axel unlocking?
If any codes post back code.
How many miles on it?
Has it ever been serviced with the GM blue transfer case fluid?

Do not use 4W on dry payment.
let it sit overnight and try it.
Also when shifting out of 4W stop and place trans in neutral or back up.

Does all shift light buttone light up for a bulb check?
To test it you will need a Transfer case capable scanner.
Is front axel unlocking?
If any codes post back code.
How many miles on it?
Has it ever been serviced with the GM blue transfer case fluid?

I only use when the ground is wet (highway driving) or snow pack....
It has 200,100 miles on it, Never serviced the tranfer case.....I had the vehicle since it had 45,000 miles..

All the shift lites come on for the bulb check....

Also I disconnected the battery for 5 minutes.....

I disconnected the vacuum hose last night (for the front hubs)....the next morning I pressed the button fo 2hi- it stayed at 2hi....drove about 1 mile after I made a stop at the gas station, it finally disengaged..

I will take to autozone to get the codes read.....

I only use when the ground is wet (highway driving) or snow pack....
It has 200,100 miles on it, Never serviced the tranfer case.....I had the vehicle since it had 45,000 miles..

All the shift lites come on for the bulb check....

Also I disconnected the battery for 5 minutes.....

I disconnected the vacuum hose last night (for the front hubs)....the next morning I pressed the button fo 2hi- it stayed at 2hi....drove about 1 mile after I made a stop at the gas station, it finally disengaged..

I will take to autozone to get the codes read.....

AZ will not be able to read Transfer case data or codes.

Find a good repair shop with a transmisionn/transfer case/engine capable scanner.

I have not read the codes yet...most places want to charge to check it out...

But I do have new information.....I noticed the lights was dimming so I turned off the the engine but kept the key ON and tried to engage (or disengage) it..... It sounds like the shift motor is stuck (its making a pulsating buzzing sound)...whether its the transfer case stuck or the shifter, im not sure....its a rebuilt encoder motor so im guessing its the encoder motor....

Even if you have haft to pay to get it checked out.
Check it out before thowing parts at it.
If lights are diming it may be a electrical problem.
Remember proper testing.
Good Luck

Actually I wasnt going to replace the part..... I was going to take it down and see if the encoder gear is seized/stripped or is it a transfer case problem......

Actually I wasnt going to replace the part..... I was going to take it down and see if the encoder gear is seized/stripped or is it a transfer case problem......

That is why you need to get it on a scanner and see where the problem is.
No use tearing it down or throwing parts at it untill you know where the problem is.

I didnt have any money this week to get a scanner, so I dropped the encoder motor...Its seized...Looks like the gasket on the encoder motor let water in and probably corroded the insides.....Well now trying to figure out if I should go new or used.....

Ok here are the codes.....I tried to get the transmission guy to clear them but he refused....something about the codes would just come back...I tried to clear them by taking out the fuse for 20 mins and it didnt work...also the " off" to "run" 5 times thing too...codes still there......
C0324-Lock Ckt Hi
HIstory
0327 encoder ckt

0387 no shift

0323 lock ckt low

0234 lock ckt hi

Its actually stuck in 4wd hi- when I put the vacuum line back the hubs lock and it shudders like im in 4wd...I took the vacuum line back off - of course.....so what am i dealing with?

That is a tough call.
The transmission man should have looked into the history codes and checked to see if 324 code for transfer case lockup solenoid/circuit was the first code set.
If the lockup solenoid or circuit is bad it will also lock up all shifting and prevent the encoder motor from shifting.

He should have done the shift test and cleared codes while he had scanner hooked up.

If you are going to repair it yourself get some good repair info like a factory repair manual for a All Data online sub and go threw the repair charts for the codes.
Also check out all wiring/circuits and coonections and plugins.
http://www.alldata.com/products/diy/index.html

Also you may need a transfer case scanner to clear codes and see what one comes BACK FIRST AND TO DO THE TESTING for the codes.
Good Luck

That is a tough call.
The transmission man should have looked into the history codes and checked to see if 324 code for transfer case lockup solenoid/circuit was the first code set.
If the lockup solenoid or circuit is bad it will also lock up all shifting and prevent the encoder motor from shifting.

He should have done the shift test and cleared codes while he had scanner hooked up.

If you are going to repair it yourself get some good repair info like a factory repair manual for a All Data online sub and go threw the repair charts for the codes.
Also check out all wiring/circuits and coonections and plugins.
http://www.alldata.com/products/diy/index.html

Also you may need a transfer case scanner to clear codes and see what one comes BACK FIRST AND TO DO THE TESTING for the codes.
Good Luck


Found a shop to clear the code...sure enough, the c0324 came back.....trans shop had a good encoder motor/and selector buttons for the dash...same results.....the motor buzzed, but didnt move...so we put mine back in....he suggested I check the connectors to the motor and check the wiring.....with a known good motor and selector the next step is wiring between TCCM and encoder motor....I will check voltage and resistance tonight on wiring harness.....

Code 324 is not a encoder motor or shift button problem.
It is a code for the transfer case lockup solenoid /transfer case brake control solenoid problem.

Could be the solenoid or wiring.
You need to get the repair flow chart for that code and go all of the way threw the repir flow chart repair.
Good Luck

Ok I got Document 555780 ....I went thru the process and got to step 6 . I had continuity up to the connector on the TCCM...The terminal was corroded just about to break off. I had to get another TCCM...I got lucky and found a guy selling a totalled blazer for parts..Nabbed it for $25. Cleaned up the terminals and sanded the metal to make sure there was a good ground. Placed anti corrosive compund on the terminals and the connectors.... Everything works fine.....

Check them wires real and plugin real good.
Does it make all of the shifts now?
The light may stay on untill the code is cleared.
Good Luck

Everything is plugged in...I soldered the wires to make sure they wouldnt come apart...It shifts in all gears but buzzes going back to 2WD. but seems to work normally..........but also the it takes about 5 seconds for the "service 4wd" light to come on......before it came on right away......

Make sure you clear codes and recheck for any coming back.
That transfer case needs service with the new GM blue transfer case fluid ever so often.
If it has not been serviced service it.
Good Luck

will do, on the codes...I changed the Auto Track II just before this went down...ill do more often from this point.....

For people who are trying to trouble shoot a problem like this, Start at the TCCM on 1999 and up, its on the passenger kick panel on the right side....check the terminals and make sure they are not corroded....clean them up and place anti corrosive compound on the terminal connector