4WD issue

Lil-j · Post by **Lil-j** » Tue Dec 25, 2012 2:54 pm

I used 4HI yesterday, I was stopped when I engaged it, in drive and it went in. Today I pushed the button and nothing, if I put the TRANS in neutral and push the button 4hi and 4lo flash a few times then it goes back to 2 hi. So I tried 4lo, in neutral, then to park then drive like the manual says. I felt the front engage and the truck moved but I had no lights on the 4x4 on the dash. And then the truck moved but not really well and the engine rev'd higher than it should as if the trans was slipping.
I didn't like that and tried to back to 2HI and it wouldn't shift out 4lo. I shut the truck off and started back up. The buttons were lit and I got it back to 2 hi. But she won't go into 4hi, the buttons don't do anything if its in drive. I don't know what's wrong

Lil-j · Post by **Lil-j** » Tue Dec 25, 2012 2:58 pm

Sorry for the bad grammer, I'm using my phone and there is lag for someone reason and I can't see the edit function

Post by **HenryJ** » Tue Dec 25, 2012 4:18 pm

Sounds like you will be in the market for a new encoder motor. Easy swap. Hard on the wallet though.
Try a reset, ( remove both battery cables, wait and reinstall ).

I lost mine in the Avalanche recently. Get it fixed before it goes to neutral and you are stuck there.

ApproachMedium · Post by **ApproachMedium** » Wed Dec 26, 2012 4:58 am

Humm so thats what that is? The old blazer went in 4 low (really 2 low since the front driveshaft is removed) on me the other day and until the light on the dash finally came up I thought the transmission was gone. I can successfully switch it from 2 high to 4 low somehow and back but it wont go in to 4 high, well wont give me a light that its in 4 high. But I would imagine that could be because the diff cable sensor is unplugged and the cable is frozen?

Boy I have a lot of work ahead of me with that thing. I wish someone would buy it though I see myself fixing it in the near future and keeping it as yet another backup car lol

Lil-j · Post by **Lil-j** » Wed Dec 26, 2012 1:28 pm

Encoder motor? I can't find that. But did come up with this
http://m.autozone.com/autozone-mobile/e ... ?id=533592

Is this right? This part would give me 4hi back, I'm asking because right now the 4 hi button will only respond if I'm in neutral, it blinks 3 or 4 times and stays in 2 hi. When I'm in park, reverse or drive the button does absolutely nothing. Does this motor turn the lights on in the cab (4x4 buttons)

Post by **HenryJ** » Wed Dec 26, 2012 10:04 pm

Transfercase motor = Encoder motor

There are four major parts- Dash switch, Transfercase module, encoder motor, and the front axle actuator.

Each of these could cause problems. My "guess" is the encoder motor.

ApproachMedium · Post by **ApproachMedium** » Wed Dec 26, 2012 10:32 pm

Question, if something like the encoder motor failed or was failing, could there be a DTC set that could be read with an advanced diagnostic code reader? I would imagine it isnt going to set a SES light since its not an engine related problem, but just like you can look at ABS faults can you look at 4x4 faults?

Lil-j · Post by **Lil-j** » Sat Dec 29, 2012 11:50 am

Ok, disconnected the battery for 10 minutes, BAM! I have 4WD again!

Now, what does that mean as far replacing the transfer case motor? I don't understand how it would need to be reset and works again. Then again I don't know much at all about push button 4wd. I'm just looking for education here.

Lil-j · Post by **Lil-j** » Sat Dec 29, 2012 4:45 pm

And it's gone again...... Wtf?

And this the time of year that I need it most, go figure.

ApproachMedium · Post by **ApproachMedium** » Sat Dec 29, 2012 5:10 pm

Sounds like the encoder. If the encoder is not giving good feedback about its position to the 4x4 control i would imagine it will try to prevent you from putting it in 4x4 so you dont get stuck in 4x4 or neutral. To reset your 4x4 module you can also just pull the fuse for it, or the plug on the unit itself which i believe is located behind the passenger side kick panel?

Lil-j · Post by **Lil-j** » Sat Dec 29, 2012 5:14 pm

I've read something about a vacuum actuator under the battery, I'm assuming battery tray. What I don't know is if this will have anything to do with the buttons on the dash switch?

ApproachMedium · Post by **ApproachMedium** » Sat Dec 29, 2012 5:16 pm

Lil-j wrote:I've read something about a vacuum actuator under the battery, I'm assuming battery tray. What I don't know is if this will have anything to do with the buttons on the dash switch?

My vac actuator was exploded and in pieces when I got my truck, and it would still go in 4x4 and tell me i was in 4x4 on the dash buttons. nothing actually worked, but the encoder would move and the dash would give me indication.

Lil-j · Post by **Lil-j** » Sat Dec 29, 2012 5:21 pm

Where is the encoder? Is it in the passenger kick panel?

Lil-j · Post by **Lil-j** » Sat Dec 29, 2012 5:32 pm

I haven't had any issues with my 4wd till now. Worked great in mud, it's just this now.
I start the truck and can normally hit 4hi and it goes in right away, try to do same now and the buttons do nothing unless I'm in neutral, it blinks 3 times and stays in 2hi, but only in neutral. I just need to know if its the encoder/transfercase motor, where it is and what to look for.

Post by **HenryJ** » Sat Dec 29, 2012 8:54 pm

It will be called a transfercase motor, or encoder motor. Search Rockauto.com for the part and it will show a picture. It is located on the side of the transfercase.

Lil-j · Post by **Lil-j** » Sat Dec 29, 2012 11:25 pm

Searched rockauto, closest thing related is this:

http://www.rockauto.com/catalog/x,carco ... type,16844

Im pretty sure this goes in the kick panel on the passenger side.

And these are transfer case motors:
http://www.rockauto.com/catalog/x,carco ... type,10323

Ok, any idea of how to diagnose which one needs replaced knowing that a reset allowed the buttons to function for a short time? I can easily replace either one but neither are really cheap. Diagnosis is the problem.

And Henry, have I thanked you lately? You kick ass buddy!

ApproachMedium · Post by **ApproachMedium** » Sun Dec 30, 2012 12:02 am

I would imagine the moving part under the truck is what is the problem. Since the controller worked after a reset. Your not the only person who has had this problem before and it seems the encoder (transfer case motor) is the more common failure part.

Post by **HenryJ** » Sun Dec 30, 2012 7:22 am

Thank you.

I go for the most common solution first. What can wear out? What has moving parts.
The front axle actuator is our first suspect since the cable and actuator are known trouble makers. The cable corrodes and battery acid eats up diaphragms. It is pretty easy to disconnect and check for function.

The transfercase control module (TCM) is electronic. Most of the time electronics work, or fail. The TCM is in the kick panel and somewhat protected from abuse. Unless you have had electrical problems like low voltage, high voltage, grounding, etc. , it has lead a pretty easy life. I am not aware of a test procedure to check them. I suspect there is a flow chart with the TCM replacement at the bottom of that list.

The transfercase motor shifts the transfercase. It has gears, brushes and a motor. It is subjected to the harsh environment of the chassis underbelly. I think it is a stepper motor, so testing it would also be difficult. Being a stepper motor is one more reason to suspect it. GM has many stepper motor problems. Throttle bodies and speedometers to name a couple. The failures that I have seen have been 7-9 years old and 100k-150k miles. It is an easy swap, so putting in a good one may be the only good answer here.

Of the two you have listed I have replaced four transfercase motors and no TCM. In my book the transferscase motor is suspect.

I am not aware of a diagnostic code , or procedure to help you in this case. There may be one that a TechII could find, but I don't have access to one of those tools. By the time you pay the minimum shop rate to have one hooked up, the money may be better spent on the replacement part? I suppose you could ask your local GM tech, but I suspect that they don't know either until they connect the TechII. Unfortunately the tech at your local GM dealer is not paid enough to know it all.
The OBDII system was designed to monitor emissions function. While it does do some diagnostics for other systems, it does not do it all. These trucks were still pretty early in the process and newer vehicles get better at diagnosing various systems. Our OBDII is blind to many issues I wish it could tell us about.

I wish I had a definitive answer, but I do not. You have to roll the dice and see what comes up. Use the best information that you can find and make your choice.

rlrnr53 · Post by **rlrnr53** » Sun Dec 30, 2012 3:30 pm

If I remember right there used to be a thread here somewhere about pulling flash codes by crossing two terminals on the ALDL connector and reading the number of flashes on the switch lights. I can't remember where it is located on the forum. OK, look at the sticky on transfercase codes at the top of this section.

Lil-j · Post by **Lil-j** » Thu Jan 03, 2013 12:25 pm

Ok, so I've decided I'm gonna change the encoder motor as soon as I have cash to do so. My next question is which one do I need? The sticker in the glove box has within the list of parts NP1. I've seen this number listed in the link I posted above for transfercase motors/encoder motors. So is NP1 the correct part for my truck? I have the 3 button switch in my truck, 2HI, 4HI and 4LO.

adrenalnjunky · Post by **adrenalnjunky** » Thu Jan 03, 2013 12:32 pm

NP1 : TRANSFER CASE (ELECTRIC) FULL RANGE

Yep - that's your transfercase build RPO code - but it is not a part number.

adrenalnjunky · Post by **adrenalnjunky** » Thu Jan 03, 2013 12:42 pm

you're looking for one that works with the NP233 transfercase. looking at rockauto.com - it's the dorman #600900, or A-1 #48107 most likely - don't take me as gospel.

JaVeRo · Post by **JaVeRo** » Sat Mar 02, 2013 12:59 pm

This will explain the 2Hi-4Lo shifting, from a post March 3, 2008 that was copied from an earlier post:

From a previous thread wrote:Straight from the service manual:

The transer case encoder motor is an assembly which houses 4 separate channels. These channels are used to indicate to the transfer case shift control module the present gear position of the transfer case or if the tranfer case is in transition between gears. The encoder motor assembly consists of an electonically conductive inner ground ring in contact with a 3 legged wiper arm. Each legs length is such that it makes contact with the conductive regions of the 4 channels. When any leg of the wiper arm is making contact with the conductive area of any channel, the encoder provides a path to ground to the inner ground ring.

During electronic shifting, the transfer case shift control module monitors the transfer case encoder circuit for the proper operating sequence. If at any time during a shift, the encoder changes from one position to any position other than the next possible position, an error counter in the transfer case shift contol module increments by 4. After the counter reaches 32, the transfer case shift control module set a DTC2, a permanent "encoder fault," and reverts to a 2HI to 4LO or a 4LO to 2HI shift pattern only. To guard against a transient, random encoder fault due to vibration, dirt electrical noise, ect., the fault counter reduces by one each time the transfer case shift control module detects a valid encoder value. The encoder must intermittently fail 25 percent of the time for the transfer case shift control module to consider it faulty and store DTC2. It is imperative that the technician test-drive the vehicle and request several shift in order for the code to properly be set.

Lil-j · Post by **Lil-j** » Thu Oct 24, 2013 9:13 pm

Ok, Bringing this thread back. I havent had a chance to get this issue fixed yet, been a rough year.

However I've got it narrowed down to this part #48107 for the new encoder motor. Also, Wanna see what you guys think, cause parts are parts, money is money and I dont have a lot of money but have a job lined up so I need 4wd asap. A buddy of mine has a 96 S10 blazer, same push button 4wd as my S10. The blazer is pretty much junk and my buddy is gonna scrap it. He says it'll start and run but not much else so I ask if it'll shift into 4HI and he says it does. So I'm thinking I should salvage the encoder motor from the blazer and put it in my truck. According to rockauto, both trucks will take a #48107, so it should work. What do ya think?

http://www.cardone.com/Products/Product ... 107&p=rock

ApproachMedium · Post by **ApproachMedium** » Fri Oct 25, 2013 4:08 am

Sounds like you should be ok, either way thats an expensive part. While your at it i would take the diaphragm thats under the battery too if its not rotted out. If that hasnt gone yet in your truck it will probably be the next thing to go. They are about $120 new from the dealer. The vac switch is cheap they are less than $20 if i remember correctly. Anyone else has any ideas? Feel free to add along

Lil-j · Post by **Lil-j** » Sun Oct 27, 2013 12:25 pm

Got the encoder motor out of the blazer today, not gonna have time to put it into the s10 today but it'll go in soon. Was not hard at all to remove once I figured out all of what I needed to do. I'll let ya know when it's installed and whether or not it works. Wish me luck.

killian96ss · Post by **killian96ss** » Mon Oct 28, 2013 10:04 am

Your problem sounds exactly the same as one I had with my 01 CC and the fix was a new encoder motor. It's possible that it is something else, but I have to agree with everyone else's suggestion to replace the encoder motor first.

Steve

Lil-j · Post by **Lil-j** » Mon Oct 28, 2013 11:22 am

I'm gonna be replacing the encoder motor today or tomorrow but wanted to ask for more info first. I took the encoder motor off of a 96 blazer that I wa not cocerned about doing it right other than gettting it out of the truck. So, when I put this one in my s10, do I need to disconnect the battery? I read somewhere about clearing relating codes before operating the new encoder motor, I only have a pocket scanner and it shows no codes, I'm ok right? Is there anything else I need to do, or not do? I only ask because I havent done this job on a truck that has to run when the part is replaced, cant afford to screw it up.

ApproachMedium · Post by **ApproachMedium** » Mon Oct 28, 2013 5:20 pm

Id disconnect the battery, the codes are codes for the 4x4 module, not emissions related codes which is probably all your pocket scanner does.

Post by **HenryJ** » Mon Oct 28, 2013 5:24 pm

It is always a good idea to pull the battery cables when working on electrical systems. That said, I didn't when I replaced my t-case motor.

Pulling the cables will reset the PCM and clear all the codes. Sounds like a good time for a fresh read, so I probably would do it.

Normally the new encoder motor is in the neutral position IIRC. You don't really know what position the used motor is in. Lets assume it was in 2wd. If that is the case pull yours and compare the position of the shaft (clocking). I am betting you will find them clocked the same. Simple bolt on and you are good to go.

If they are different. Do not try to change the position at the motor. You will damage it trying to move it. Turn the shaft from the transfercase. Be careful not to burr the shaft. Use finesse, not brute force.
Careful of the plastic electrical connectors. By now some of those retention clips may be getting brittle?

Really an easy swap. you will do fine.

Lil-j · Post by **Lil-j** » Tue Oct 29, 2013 12:53 pm

Ok, I did the swap last night, everything well except for the drive shaft, I hate needle bearings.

I had figured to look at what position the transfer case shaft was in compared to the TC motor, mine the matched the replacement one and it went on easy. Got the job done, disconnected the battery and left the truck sit for the night.

Today I reconnected the battery, fired the truck up and drove out of the garage, took a turn around the block. Odd, the radio pre-sets were still there...then the truck died going around a turn. Pull over, restart, go on my way. Go back home, shift into neutral, push 4HI, same as before, blinks 3 times and back to 2hi.

As before, I can only get 4LO and 4LO sucks. I've never used it before but I dont think it functions right. Push the button from neutral, then shift into drive and you can feel that it's in 4LO. When trying to move it's like trying to move a stick shift from 4th gear, engine rev's and truck moves but really goes slow....like a tranny slip. Still no 4HI though.

So, either the encoder is bad (very well could be), some other electrical/vacuum problem, or the transfer case is bad/going bad...

Questions, should the front drive shaft be able to free spin when the truck is parked? I'm trouble shooting in my head at the moment, seeing as how the front diff was engaged for 4LO, I shouldnt have a vacuum problem then, right?
I'm pretty much left with encoder motor or transfer case........

ApproachMedium · Post by **ApproachMedium** » Tue Oct 29, 2013 1:00 pm

On these trucks you are supposed to be able to shift the 4 High when its in drive. I have never done it in neutral, only for 4 low. you can do it to 4 high while its moving too, at least thats what its supposed to be able to do with the push button system.

When I was under my truck last night I dont recall my front drive shaft being able to move but the tires moved freely on the front. Maybe you need to look at a new Tcase from the junk blazer as well.

Lil-j · Post by **Lil-j** » Tue Oct 29, 2013 1:56 pm

Speaking of of the button shifter. The button's wont respond unless I'm in neutral, not park or drive. The owners manual says you should be able to go from 2HI to 4HI and any speed.

I may have to look into the other transfer case.

roadrunner · Post by **roadrunner** » Tue Oct 29, 2013 3:43 pm

Before you get too involved you might try a trick that worked for me. Remove battery cable, remove pass side kick panel, unplug T-case control module hidden there for a few seconds, plug back in, put kick panel back, hook battery back up, then try to see if your buttons work correctly. This is the one certain way to remove any codes in that system. If still not working correctly you may need a new dash-button switch set. This does not however rule out the possibility you had a bad encoder and replaced it with another bad one but it will definitely clear any codes. Be aware the module keeps track of successful vs unsuccessful shifts so if a problem still exists after a number of shifts (assuming it will shift) codes may return indicating a remaining problem. In my travels and troubles I have had at different times had to replace all the electronic components of the system on my truck as well as the vacuum components.
If you have your owners manual there is a procedure in it to force shift the transfer case. I must tell you if the encoder is out it will not however work to force the shift. Hope this helps you.

killian96ss · Post by **killian96ss** » Tue Oct 29, 2013 6:51 pm

The front drive shaft should move freely if the trans is in park and the t-case is still in 2wd. If it won't move at all, your transfer case or front diff must be engaged. If you are able to get in and out of 4LO then your t-case and front diff are both working ok. About a month or two after the encoder motor was replaced in my 01 CC, the dash switch went out causing similar problems as when then encoder motor stopped working correctly. I'm not a big fan of the electronic transfer cases for this reason. My 88 S10 has a manual shift transfer case and Posi-Loc manual controlled font diff. I have never had any problems going in and out of 4wd with this setup and I also have the ability to run in 2 LO for great low end torque when crawling or pulling out other stuck vehicles. If you can, get the dash switch out of that Blazer, and swap them to see what happens.

Steve

Lil-j · Post by **Lil-j** » Tue Oct 29, 2013 11:00 pm

Thank you two for the good info, Henry as well.

Truck is back in the garage and I'm gonna start to play with it again tomorrow. For starters I'll disconnect the battery and check the box behind the kick panel, unplug it, clean the terminals, plug er back in. AS long as the battey is disconnected, might as well pull it out and the battery tray and check the (cant think of the name right now) part with the rubber diaphram and the cable.

Now, the transfer case buttons wont respond at all unless the trans is in neutral. While I'm in neutral, I can go into 4lo and back into 2hi, like steve said, front diff and TC should be ok. When I try to shift into 4hi, the buttons blink a few times then stays in 2hi. While the lights are binking, the box in the kick panel clicks (sounds like a relay clicking) and I can hear the encoder motor try to shift but stop.
When it goes into 4lo.......
This guys describes it perfect, this is how my truck is in 4lo, pretty much useless. Go to the 4:00 mark. The rest of what he says is good too.
http://www.youtube.com/watch?v=CbEF6PyJdU0

After this tomorrow, I'm gonna go out and retrieve the button set and transfer case control module from the blazer, hell, if I could I'd bring the whole truck home and gut the entire drive train out of it.
I also gotta look into the force shift thing, I dont recall seeing that in the manual.....

I'll keep ya posted fella's.

roadrunner · Post by **roadrunner** » Wed Oct 30, 2013 12:12 pm

When my encoder motor failed I had the identical problem of only available to be able to shift from 2hi to 4lo. 4hi would not work at all. Tried all the above mentioned fixes including the owners manual forced shift. What goes bad in the encoder motor (generally) is the position indicator that tells the motor where to stop. Lose 4hi and there's no way it will stop in that position. Unfortunately I'm speaking from experience on that one and dis-assembled the encoder to see what caused the problem. Later on I had the aforementioned dash switch failure and a particularly annoying front light switch failure as well not to mention at an even later date the screws coming loose on the vacuum shift pod allowing everything to function as indicated on the dash but the front would not engage. Also have replaced the T-case vacuum switch due to it starting to leak fluid into the system. So as you can see I'm not just guessing here. Hope this information helps you out.

Lil-j · Post by **Lil-j** » Wed Oct 30, 2013 1:23 pm

In the end, could very well be the encoder motor. Your right, I've read that before about the sensor in it going bad. I'm just trying to rule out other things while I'm at it.

I've got the battery and tray out right now. Trying to see if the cable is froze up, or the thing with the diaphragm is bad. Should I be able to squeeze the diaphragm thing all the way in or no? Mine only goes in a little, don't know if it should be able to go in more. Thinking the cable is seized up, it doesn't much at all when I grab just the cable. Ive read about squirting some silicone/WD40/PB or whatever to free it up, thoughts on that?

Lil-j · Post by **Lil-j** » Wed Oct 30, 2013 2:49 pm

Ok, seperated the cable from the diaphragm, diaphragm squeezes all the way in. When doing I can air escaping from near the firewall. Traced it to a line that I found zip tied to the TRANS dipstick. It's a little floppy cap thing on it that will jump if the diaphragm is squeezed quickly enough. Is this ok?? I don't have too much experience with vac systems. Is it a pressure release maybe? Idk..

Also found the end of the cable to the front diff. I'm gonna try to unthread it. And squirt something in there to free it up.

Post by **HenryJ** » Wed Oct 30, 2013 3:28 pm

That tube is the vent for the switch. It is where it should be and sounds like it is good.

Lil-j · Post by **Lil-j** » Wed Oct 30, 2013 5:20 pm

How bout luning the cable? Do I squirt some PB down the tube the cable is housed in?

Lil-j · Post by **Lil-j** » Wed Oct 30, 2013 5:21 pm

*lubing

Post by **HenryJ** » Wed Oct 30, 2013 6:31 pm

I would use something that acts as a lubricant if anything at all. Some are solvent/penetrants. Those in your area will know better than I. My high desert climate is friendly to the cables and not an issue for me. Your salt and moisture is a game changer.

roadrunner · Post by **roadrunner** » Wed Oct 30, 2013 7:23 pm

Lil-j wrote:In the end, could very well be the encoder motor. Your right, I've read that before about the sensor in it going bad. I'm just trying to rule out other things while I'm at it.

I've got the battery and tray out right now. Trying to see if the cable is froze up, or the thing with the diaphragm is bad. Should I be able to squeeze the diaphragm thing all the way in or no? Mine only goes in a little, don't know if it should be able to go in more. Thinking the cable is seized up, it doesn't much at all when I grab just the cable. Ive read about squirting some silicone/WD40/PB or whatever to free it up, thoughts on that?

Lubing the cable is a good idea but bear in mind if the gears in the differential aren't positioned so they can engage completely the cable may be okay but not move very far without turning one of the axles to allow full engagement. PB would be my personal choice for the lube job.

Lil-j · Post by **Lil-j** » Wed Oct 30, 2013 7:58 pm

Thanks fellas, PB it is. But to actually lube the cable do I just spray little squirts into where the cable retracts into the cable sheath? I'm doing this watching it suck into the sheath already.

I checked the vacuum switch on the transfer case above the encoder motor, functions fine. The check ball moves in and out as it should. There was a little ATF in there but not much....

Gonna lube the cable some and see if that frees up.

Lil-j · Post by **Lil-j** » Thu Oct 31, 2013 12:19 pm

Ok, I put it all back together, still the same issue. The 4x4 actuator retracts when the Tcase goers into 4lo, still not sure in the front diff is fully engaged but I cant free spin the front drive shaft. I know the vac system works good. Pretty sure its the encoder motor...

Tomorrow I'm gonna go pick over the blazer, grab the 4x4 selector switch, Tcase module, Tcase actuator and cable, Tcase switch, front drive shaft and maybe even the whole damn transfer case!
Wish me luck.

roadrunner · Post by **roadrunner** » Sat Nov 02, 2013 4:54 pm

Lil-j wrote:Thanks fellas, PB it is. But to actually lube the cable do I just spray little squirts into where the cable retracts into the cable sheath? I'm doing this watching it suck into the sheath already.

I checked the vacuum switch on the transfer case above the encoder motor, functions fine. The check ball moves in and out as it should. There was a little ATF in there but not much....

Gonna lube the cable some and see if that frees up.

I've never had to dis-assemble the cable to lube it. Just let it soak in down the cable. REPLACE THAT VACUUM SWITCH PRONTO!!!

Failure to do so will cause you more grief than you know contaminating the vacuum system and ruining other things in that system. NO fluid is permissible in that vacuum side of the switch.

killian96ss · Post by **killian96ss** » Sat Nov 02, 2013 8:03 pm

roadrunner wrote:REPLACE THAT VACUUM SWITCH PRONTO!!! Failure to do so will cause you more grief than you know contaminating the vacuum system and ruining other things in that system. NO fluid is permissible in that vacuum side of the switch.

He is right, if your tranfer case vacuum switch had any fluid in it, you should replace it ASAP. The switch should be less than $20 which is cheap compared to what it will cost if ATF gets into the HVAC system. The newer gm part # 89059420 replaces the older leak prone switch. Read the "revised transfer case switch" topic in this forum for more info.

Steve

Lil-j · Post by **Lil-j** » Tue Nov 05, 2013 1:55 pm

http://www.autozone.com/autozone/parts/ ... 2180_13424_

http://www.autozone.com/autozone/parts/ ... 2180_15907_

Which one?

roadrunner · Post by **roadrunner** » Tue Nov 05, 2013 6:55 pm

Lil-j wrote:http://www.autozone.com/autozone/parts/ ... 2180_13424_

http://www.autozone.com/autozone/parts/ ... 2180_15907_

Which one?

NEITHER!! Use the GM part. It has been redesigned to eliminate the problem. The newer gm part # 89059420 replaces the older leak prone switch. Read the "revised transfer case switch" topic in this forum for more info.
May be a couple bucks higher but definitely worth it.

ApproachMedium · Post by **ApproachMedium** » Tue Nov 05, 2013 7:16 pm

I agree. Stay away from the 7 dollar ebay specials too. Chances are made in china and will fail quickly.

Lil-j · Post by **Lil-j** » Wed Nov 06, 2013 10:40 pm

Just put a new encoder motor in. Battery disconnected. AND TC control module unplugged while doing the swap. Same problem. No 4hi, only 2hi and 4lo. Wtf....

Transfer case switch replaced yesterday.

All my trouble shooting kept leading back to encoder, replaced it. Still a no go.

killian96ss · Post by **killian96ss** » Thu Nov 07, 2013 2:48 pm

Have you already read through the "transfer case codes" topic stickied in this forum? There is alot of good info there that might help you track down the problem before you replace anything else. If you read through it you will see that the most common problem is not being able to shift into 4HI and how to diagnose what is causing the problem by reading the code (flashing lights on the dash switch) which is done by jumping terminals on the OBD2 connector under the dash. There are 4 possible codes. Knowing which one you have will help narrow down your problem.

Steve

roadrunner · Post by **roadrunner** » Thu Nov 07, 2013 10:23 pm

killian96ss wrote:Have you already read through the "transfer case codes" topic stickied in this forum? There is alot of good info there that might help you track down the problem before you replace anything else. If you read through it you will see that the most common problem is not being able to shift into 4HI and how to diagnose what is causing the problem by reading the code (flashing lights on the dash switch) which is done by jumping terminals on the OBD2 connector under the dash. There are 4 possible codes. Knowing which one you have will help narrow down your problem.

Steve

I agree with Steve. It sounds like you are getting down to either the dash switch or the front indicator switch or perhaps (I hope not for your sake) wiring problems. I admit I am surprised the encoder did not fix the problem as the problem you described is exactly what mine was doing when mine went out and when I discovered it was a position sensor failure in the encoder at the root of it.

Lil-j · Post by **Lil-j** » Thu Nov 14, 2013 7:58 pm

Trucks fixed!

A buddy of mine two states away was at the junk yard, asked me if I needed anything. For grins I said grab a transfer case control module if you find one. He did, shipped it out, I got it yesterday, put it in today, now I got 4HI back!

Lil-j · Post by **Lil-j** » Thu Nov 14, 2013 8:23 pm

Also, I mentioned a few weeks ago about my friends 96 blazer that he was scrapping. I got the encoder motor off it originally and nothing else at that point. Later I went back and spent 6 hours going through and tearing stuff off of it. I figure at the very least I'll get the experience of removing the parts, plus if I dont want to use that part I'll have core on a new part. I took the alternator, A/C compressor, front shifter cable and actuator, MAF sensor which looks brand new, plus he a had another MAF sensor I took. For grins I took the front passenger seat which I'm glad I did cause I found the 4x4 button switch that fits my truck (96 was differant). I forgot to get a pic of all of it though.

Biggest thing I took was the transfer case! The Tcase look's great inside except for the fluid looked horrible. But the chain and sprockets look great, shift and mode fork look great, the little plastic pads look like new. I'm not sure what I'm gonna do with it yet but I'll figure it out soon.

Lil-j · Post by **Lil-j** » Thu Nov 14, 2013 8:28 pm

rlrnr53 · Post by **rlrnr53** » Fri Nov 15, 2013 4:54 pm

Do you remember how it goes back together?

CraigS · Post by **CraigS** » Mon Dec 16, 2013 10:25 pm

Hi, my first post here since joining. I actually have a 2000 Blazer but you folks seem to be the most tech savvy of any of the forums.

I'm having the same shifting problem that the other posters seem to be having; 2 Hi and 4 Lo but no 4 Hi. Checked the code, cleared it, and it immediately returned. Everything points to the motor.

Before I replace it though, I wanted to check with the experts that my actuator modification didn't create the problem. When I got the truck the vacuum lines to and from the transfer case were rotten/missing. I bypassed the switch on the transfer case completely (plugged all of the ports) and ran a vacuum line through a push-pull vacuum switch under the dash straight to the actuator. The now manual actuator works fine, and 4WD worked fine for about a dozen times after my modification. I've seen references to a vacuum switch on the firewall (no sign of that) and to some sort of sensor on the front axle, both of which supposedly send information to the TCCM. Did I bypass some widget that had a delayed reaction in preventing 4 Hi from engaging? Or could it really just be the motor?

Thanks, Craig

Post by **HenryJ** » Tue Dec 17, 2013 5:56 am

Sounds like you have it figured out. The only items in the mix that could be an issue would be the switch and module. The transfercase motor (encoder) is more likely as it is know to fail. That would be my first suspect in this case.

CraigS · Post by **CraigS** » Sat Dec 28, 2013 8:30 pm

The rebuilt Dorman motor arrived today from Rock Auto and it looks like it might be possible to swap it out myself without removing the yoke. Question about the part where the transfer needs to be in 4Hi when installing it. The instructions say to manually turn the shift shaft with a crescent wrench if necessary to line it up with the preset motor position. That sounds a little too simple for anything on these newfangled servo/solenoid/vacuum/microchip controlled vehicles. Is it really that evident once I get the old motor off?

Thanks, Craig

Post by **HenryJ** » Sun Dec 29, 2013 8:27 am

It is. The shaft has half a dozen raised splines and a recessed side. It won't be too hard to tell where it is clocked.
Taking the old one off, compare the two and see which way you need to turn the shaft , if any. It really is that easy.
Clean up the bolts and apply a little fresh LockTite thread locking compound to the threads when you install them. They are fairly close to the driveshaft and we don't want them backing out.

Lil-j · Post by **Lil-j** » Mon Dec 30, 2013 10:42 am

Splined shaft on the Tcase shift shaft, that goes to the encoder? Huh?