Code C0327 Transfer Case Motor-Encoder Issue (2005 Chevy Suburban Z71) or Similiar
January 2nd, 2021, 10:42 AM
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Code C0327 Transfer Case Motor-Encoder Issue (2005 Chevy Suburban Z71) or Similiar
I have a 2005 Chevy Suburban Z71 4-push-button 4WD drive system. I got the Service 4WD light on the cluster panel. I used my Autel OBDII bluetooth scanner, code came back C0327. Chevy says the issue is straightforward, replace the Transfer Case Control Motor (TCCM) encoder inside the motor. I ordered the encoder on RockAuto for about $32, once it came in I removed the TCCM.
*NOTE: It's much easier to get the bolts out of the TCCM when removing the drive shift, make sure you mark your drive shaft with a grease pencil so you install it the same way it comes out.
I know some folks get the TCCM out without doing so, I found removing the drive shaft saved time. Once I removed the TCCM, I got it on my bench and opened it up. Plot twist there was freaking fluid inside the case, looks like water got in, mixed with the gear grease and was a strange color. With water being in the case I could not trust there was not a short in the motor. This all happened a day before Christmas Eve, ordering a TCCM from RockAuto was out of the question. I planned on taking a trip on Sunday and the part would not come in until Monday. I needed my Burb up and going without worrying if the 4WD would lock up on the highway. I went to Napa on Christmas Eve and bought a Remanufactured Transfer Case Motor Part# TCM-48113 for $229. Autozone had one for $309, I passed due to the $100 difference.
Napa required my old TCCM with a Core refund price of $27. The refurb TCCM came with two new grounding bolts, which I thought was cool. I hooked the TCCM up without installing to get the actuator in the right position. For some reason it was not in the neutral position (keep this in mind), after hooking it up I put the key in the ignition and turned the key forward all the way without starting. The Service 4WD light was still on which should not have been, all lights on the 4-pushbutton selector were not lit up as they were before.
*NOTE: When turning the key the push buttons lit up for about 2 seconds and all went blank.
This did not happen before putting the new motor in, I still had lights showing. At this point I was frustrated, my thought was I had two issues and just discovered the second problem. I started checking fuses, by the way some forums talk about an Automatic Transfer Case (ATC) fuse, in some Suburbans and Chevy’s it would be the TREK fuse, don't let this become you chasing your tail. Also, make sure to check your fuses on the inside driver side, there is a 4WD fuse to make sure it's not blown. I checked all fuses, no issues, got my multi-meter and checked many others. All fuses were good, so next, I thought maybe I have a grounding issue. The ground cables are underneath close to the drive side rear of the tire. There are two of them, I unbolted all of them, took my wire brush on a drill and cleaned up the whole area. I then installed the new bolts that came with the TCCM. At this point I am happy I knew this would fix the problem. Went back in the car, turned the key forward, push-buttons still did not light up and the Service 4WD still came on the cluster. I am now pissed. So I went to Autozone and bought a new 4-push button 4WD selector, got back home installed it….still no lights.
You can imagine I was on fire now. I have been troubleshooting the issue for a while and was out of options. I decided to put my code reader back on and see if any new codes came up. BAM! Three new powertrain codes came on. I was very confused but then decided maybe I have a bad refurbed TCCM. I went to AutoZone returned the 4-pushbutton selector and bought their TCCM for $309, Dorman Transfer Case Motor, Part# 600-910. Remember, this TCCM comes in the NEUTRAL position. Based on Dorman install instructions on their website, manually put your transfer case in neutral. Make sure your tires are blocked and emergency break is on. For other Chevys with similar transfer cases the neutral position is between the 7 and 6 oclock position. Match it to the TCCM and you won't have any issues. I tried doing it other ways I do not suggest doing it another other way than matching the transfer case shift **** to the new TCCM. If you do any other way like I did you will probably have a meltdown. After making the transfer case adjusta prayer to the Lord. I bolted on the new TCCM, turned the key forward, the Service 4WD light DID NOT come back on. The cluster panel was showing the vehicle mileage. The 4-push button selector lit up and a red light was on for neutral. Celebration happened!
*NOTE: Make sure to blow out the TCCM bolt holes with air, there was a lot of lock tight in them. I did not use lock tight, instead I put anti-seize on each bolt.
After the TCCM was installed I cleaned off the splines to the drive shaft, put new grease on them. Remember there is a boot that goes over the drive shaft splines. When removing the drive shaft the first time the boot was held on by the original clamps. They are the ones you have to break off with a flat head or snip them off. I cleaned the boot off, put grease on the inside and then slid over the shaft splines to where the boot gets fastened to. I then slide the shaft back into the transfer case. Once this was completed I adjusted the boot and put new clamps on.
*NOTE: When working on the transfer case you have to remove the skid plate on the Z71 model.
Once finished with that end I moved to the other side and installed the front drive shaft knuckle back to the front differential. After this I reinstalled the skid plate. Once I finished buttoning up all this I went back in the car, turned the key forward, put the truck in neutral and then hit the 2-Hi on the selector. The TCCM made the shift project complete!! I did check and make sure it would cycle to Auto and 4-Hi, it shifted without issues.
*NOTE: If you try putting the truck in 2-Hi without having the truck in neutral it might not work. For safety reasons the computer wants the trucks transmission in neutral before the 2-Hi selection is made. This is the same when putting the transfer case back in neutral in the event you have to tow your vehicle.
Sorry for the long post I wanted to cover everything that other forums did not hit. This project overall took me two days, I am hoping this will prevent some of you from hanging your head like me.
Dustin
*NOTE: It's much easier to get the bolts out of the TCCM when removing the drive shift, make sure you mark your drive shaft with a grease pencil so you install it the same way it comes out.
I know some folks get the TCCM out without doing so, I found removing the drive shaft saved time. Once I removed the TCCM, I got it on my bench and opened it up. Plot twist there was freaking fluid inside the case, looks like water got in, mixed with the gear grease and was a strange color. With water being in the case I could not trust there was not a short in the motor. This all happened a day before Christmas Eve, ordering a TCCM from RockAuto was out of the question. I planned on taking a trip on Sunday and the part would not come in until Monday. I needed my Burb up and going without worrying if the 4WD would lock up on the highway. I went to Napa on Christmas Eve and bought a Remanufactured Transfer Case Motor Part# TCM-48113 for $229. Autozone had one for $309, I passed due to the $100 difference.
Napa required my old TCCM with a Core refund price of $27. The refurb TCCM came with two new grounding bolts, which I thought was cool. I hooked the TCCM up without installing to get the actuator in the right position. For some reason it was not in the neutral position (keep this in mind), after hooking it up I put the key in the ignition and turned the key forward all the way without starting. The Service 4WD light was still on which should not have been, all lights on the 4-pushbutton selector were not lit up as they were before.
*NOTE: When turning the key the push buttons lit up for about 2 seconds and all went blank.
This did not happen before putting the new motor in, I still had lights showing. At this point I was frustrated, my thought was I had two issues and just discovered the second problem. I started checking fuses, by the way some forums talk about an Automatic Transfer Case (ATC) fuse, in some Suburbans and Chevy’s it would be the TREK fuse, don't let this become you chasing your tail. Also, make sure to check your fuses on the inside driver side, there is a 4WD fuse to make sure it's not blown. I checked all fuses, no issues, got my multi-meter and checked many others. All fuses were good, so next, I thought maybe I have a grounding issue. The ground cables are underneath close to the drive side rear of the tire. There are two of them, I unbolted all of them, took my wire brush on a drill and cleaned up the whole area. I then installed the new bolts that came with the TCCM. At this point I am happy I knew this would fix the problem. Went back in the car, turned the key forward, push-buttons still did not light up and the Service 4WD still came on the cluster. I am now pissed. So I went to Autozone and bought a new 4-push button 4WD selector, got back home installed it….still no lights.
You can imagine I was on fire now. I have been troubleshooting the issue for a while and was out of options. I decided to put my code reader back on and see if any new codes came up. BAM! Three new powertrain codes came on. I was very confused but then decided maybe I have a bad refurbed TCCM. I went to AutoZone returned the 4-pushbutton selector and bought their TCCM for $309, Dorman Transfer Case Motor, Part# 600-910. Remember, this TCCM comes in the NEUTRAL position. Based on Dorman install instructions on their website, manually put your transfer case in neutral. Make sure your tires are blocked and emergency break is on. For other Chevys with similar transfer cases the neutral position is between the 7 and 6 oclock position. Match it to the TCCM and you won't have any issues. I tried doing it other ways I do not suggest doing it another other way than matching the transfer case shift **** to the new TCCM. If you do any other way like I did you will probably have a meltdown. After making the transfer case adjusta prayer to the Lord. I bolted on the new TCCM, turned the key forward, the Service 4WD light DID NOT come back on. The cluster panel was showing the vehicle mileage. The 4-push button selector lit up and a red light was on for neutral. Celebration happened!
*NOTE: Make sure to blow out the TCCM bolt holes with air, there was a lot of lock tight in them. I did not use lock tight, instead I put anti-seize on each bolt.
After the TCCM was installed I cleaned off the splines to the drive shaft, put new grease on them. Remember there is a boot that goes over the drive shaft splines. When removing the drive shaft the first time the boot was held on by the original clamps. They are the ones you have to break off with a flat head or snip them off. I cleaned the boot off, put grease on the inside and then slid over the shaft splines to where the boot gets fastened to. I then slide the shaft back into the transfer case. Once this was completed I adjusted the boot and put new clamps on.
*NOTE: When working on the transfer case you have to remove the skid plate on the Z71 model.
Once finished with that end I moved to the other side and installed the front drive shaft knuckle back to the front differential. After this I reinstalled the skid plate. Once I finished buttoning up all this I went back in the car, turned the key forward, put the truck in neutral and then hit the 2-Hi on the selector. The TCCM made the shift project complete!! I did check and make sure it would cycle to Auto and 4-Hi, it shifted without issues.
*NOTE: If you try putting the truck in 2-Hi without having the truck in neutral it might not work. For safety reasons the computer wants the trucks transmission in neutral before the 2-Hi selection is made. This is the same when putting the transfer case back in neutral in the event you have to tow your vehicle.
Sorry for the long post I wanted to cover everything that other forums did not hit. This project overall took me two days, I am hoping this will prevent some of you from hanging your head like me.
Dustin
Last edited by Dustin Ryan; January 2nd, 2021 at 10:44 AM. Reason: Tag edits
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