H3 Transfer Case Control Module

[tslevin95]

I'm having trouble finding the exact part number for a Transfer Case Control Module (TCCM) for my 2006 H3. If anyone knows the part number, that would be great.


Also, I will be installing it myself and wanted to know how exactly to get to the module. Do I need to remove the right side dash panel and it's right there?


Thanks in advanced!

 

[4speedfunk]

Ii didn't realize the H3 had such a device. I thought it only had the control panel (at the dash) and the encoder (at the t-case).
I know 08-up models have separate PCMs & TCMs and 07-down had them combined. These are located on the exterior of the firewall by the coolant tank. Perhaps these are what you're looking for?

 

[Burtor]

WAIT! Yes the TCCM is a separate device. It's basically a 'dumb' little motor driver which also lights up your dash lights. It doesn't seem to have much feedback beyond the buttons above your radio, the shifter knob position, and the transfer case motor actuator unit.
Why do you want one? Do you want one? I have an extra one in working order because I thought mine was bad. I could send it your way, in exchange for money. ($30 plus shipping? I don't really care actually) Turns out I had a different problem that I solved instead.
Is there a problem with your transfer case shifting? I've just come out of a deep-dive with this system so I'm feeling like I know it pretty well.

What noises is it making? You can listen with the engine off.
Here's how;
With the ignition in the ON position and the shifter in park you may shift between 4HI and 4LOCK.
With the ignition in the ON position and the shifter in NEUTRAL you may shift between 4HI, 4LOCK, and 4LOW.

Starting in 4HI you press the button to shift to 4LOCK, then the 4LOCK light will blink and the transfer case shifter motor will make a knocking or pulsing sound when rotating to "bump" the transfer case into 4LOCK.
If you're in 4LOCK and press the button to shift to 4HI, then the 4HI light will blink and the transfer case shifter motor will make a smooth rotational movement to shift the transfer case back into 4HI.
The transfer case shifting motor will make a smooth sound to shift into 4LO from either gear I believe, but I needed the vehicle in neutral. Otherwise the light would blink and nothing would actually happen.

You can remove the shifter motor without draining any transfer case fluid, there is a seal which prevents anything from leaking.
You can then mark its position, likely 4HI, with a sharpie or a scratch awl to keep a record where it started.
Then, you can watch it "shift" while hanging off of bottom of the vehicle. You can also test if it is rotating by touching the motor leads to a 12v jump battery and watching it turn in each direction.

Also, a simple fix might be fiddling with and jostling the shifting buttons on the dash. I hear they like to get stuck, which causes the module to throw an error up on your dash display. Once unstuck they fix themselves.

To answer your question directly though, the part numbers are as follows;
GM 24236866 is the "MODULE. Transfer Case Shift Control" which I found used on ebay for $50, and lives behind your glove box. The cover is the rounded shaped thing that is the right cover of the dash board, unacessable once the door is closed. You remove it by first removing the couple snaps on the front of it (push in the center bit, then pry them straight up and out), then popping it out the side. It's got the same snaps as the radio bezel and a bit of pressure will release it.
Here's a diagram from the manuals that Schwarttzy posted http://schwarttzy.com/h3-hummer/ open up the manual for Hummer H3 – Transfer Case, and the TCCM is shown on page 4.
If your motor is bad, like mine was, the part number is GM 89059688, but I bought the Dorman 600-908 aftermarket replacement part, BUT be careful because the motor power leads were swapped on mine so clockwise was counter-clockwise and visa-versa which was the real headache in the whole thing for me. Once I figured that out I swapped them and it worked like a charm!

So, what is really wrong? Tell us all about it, hopefully it's an easy fix!

 

[4speedfunk]

Good info. I had no idea there was such a thing.

 

[tslevin95]

Burtor,

So what is happening is that when I'm in low speeds and making a turn my H3 will lock up. This is due to it being in 4-hi LOCK. I had the t-case motor encoder replaced (didn't solve the problem). I had the plastic fork replaced inside the t-case (didn't solve the problem). So the only things left is the TCCM and the buttons. When I used the buttons, they seem fine and no noticeable sticking, I cleaned them with compressed air too. While in neutral I went from 4 hi to 4 low LOCK and you can hear the knocking noise, but when I'm in either 4 hi or 4 hi LOCK and moving between the two, there is no knocking or smooth rotational movement. There is no movement at all that I noticed. This is with the engine on, so today I will try it with the engine off like you recommended. I will update you after I do so. Also, because of that I believe the buttons are fine and that the TCCM is the issue. I'm not receiving any warning message of "serv 4wd" on my dash display.

I ordered the TCCM yesterday. The part number is 24251917 since I don't have the adventure package and confirmed with my VIN with several dealers. It's supposed to come later next week, so I will update you if that solved the problem or not after I install it.

Thanks for your reply.

 

[Burtor]

Hmmm.

Have you tried shifting it between modes manually? With the motor actuator removed, you should be able to turn the shaft yourself to at least put your vehicle into 4HI (free) mode for the time being. You can then manually apply power to rotate the motor actuator while off the vehicle to put it in 4HI and put it back on. This will keep you in 4HI (free) mode as long as you aren't pressing the buttons.

Now, troubleshooting wise. You should remove the motor again and watch it rotate. You should see it go to each distinct position when pressing the buttons, even when removed from the transfer case and just hanging beneath the vehicle.
I used multiple colored sharpies to draw lines at each position so I could confirm it was returning to each distinct spot every time.

You can also test what mode the transfer case is actually in by lifting up the various corners of the vehicle and watching the different wheels turn. With the transmission in neutral and the transfer case in 4HI (free) you should be able to lift any one wheel alone and turn it yourself. Once you shift the transfer case into 4HI LOCK, it should no longer turn alone, but you would need at least one other wheel off the ground too.

I have the 2007 H3, also without the adventure package, as in, I can't lock my rear differential.
Good luck, and I'm looking forward to hearing how this turns out!

 

[4speedfunk]

So what is happening is that when I'm in low speeds and making a turn my H3 will lock up. This is due to it being in 4-hi LOCK.

Is it actually shifting itself into 4HI-Lock?
Does the 4HI-Lock button flash and go solid on its own?
Do you get any "Service Stabilitrac" or other warnings on the DIC?

If the t-case is in 4HI-Street and it feels like its binding...then I would strongly suggest taking a look at the front axle. Especially, if there are no warning lights or trouble codes. Worn half-shaft CV's can sometimes do weird stuff like this. So can worn spider gears inside the front diff. By chance does this happen in sub-40 degree weather? If so, it could be the oil in the front diff. Thick, cold, 85w-90 can cause the spiders to stick and it feels like a locker until it gets warmed up. Full synth 75w is the cure.

You might also try removing the front driveshaft, and driving around for a few days in 4HI-Lock. If the symptoms persist without the front driveshaft...you'll know for sure the problem is in the front axle.

 

[tslevin95]

It feels like its in 4hi lock. I had the t case chain replaced last week and the issue has gotten worse. The problem would only occur when I turned the wheels fully and sometimes the problem wouldn't happen at all, but now (I guess from the new t case chain being tight) it starts to happen when I turn the wheel at all in either direction forward or back at low (parking lot) speeds.

When I turn there grinding noise and the car struggles, jumps/hops a bit too. Then it comes to a stop if you have the wheels turned fully. If you are driving straight there is absolutely no problems, at all speeds including highway. The buttons work fine and switch over as normal. I get no warning messages or check engine light. But when I either unplug the TCCM or the t case selector buttons I do get a message on the odometer area. For the buttons it says "serv 4wd" for the TCCM it said something about traction control.

After originally taking it to a Chevy dealer and having them do a diagnosis, they said that the problem was resulting from the t case motor encoder and the TCCM. I had the motor encoder replaced (problem not fixed) and will be replacing the TCCM myself this Thursday. I also ordered the t case selector buttons to swap out and see if my current ones are faulty.

Hopefully the TCCM or the new buttons fixes this issue and hopefully that made sense.

I will keep you guys updated.

 

[alrock]

4speed has some good - and cheap - troubleshooting recommendations

 

[650Hawk]

Definitely keep us updated; interesting problem.

 

[Peep]

Had to change mine twice. Fixed so much both times!

 

[tslevin95]

Had to change mine twice. Fixed so much both times!

The TCCM? What was wrong with yours and what did replacing the TCCM fix?

 

[Mb30sdl]

Your problem is whomever rebuild your t-case installed springs on wrong shaft. Take it to a person that knows how to do this right and it will cost u some more$$. Fork will need to be replaced again.

 

[4speedfunk]

First you should make sure its the t-case that's actually causing the problem. Everything you describe can also be caused by a front diff problem. Front diffs fail about 5 to 1 to transfer cases.

Given the cost...10 minutes with two wrenches (to pull the front driveshaft) is very cheap way to know for sure. If the truck did it before...and you already had the t-case apart...and its doing it again...then maybe the problem is not the t-case at all.

 

[tslevin95]

First you should make sure its the t-case that's actually causing the problem. Everything you describe can also be caused by a front diff problem. Front diffs fail about 5 to 1 to transfer cases.

Given the cost...10 minutes with two wrenches (to pull the front driveshaft) is very cheap way to know for sure. If the truck did it before...and you already had the t-case apart...and its doing it again...then maybe the problem is not the t-case at all.

Is there a thread or some type of instructions to show how to remove the front driveshaft?

 

[tslevin95]

Update: I installed the new TCCM. The problem still persists.

So I looked a the invoice of when I took it to the Chevy dealer. They told me that the motor encoder and TCCM had to be replaced, this is verbatim what the invoice said:

Customer states vehicle will not move when turning RT or left
When running towed in
Code C0306. Unknown 4WD position control
Encoder motor shorted or grounded in control - necessary to
Replace encoder motor and transfer case control module
$1240.00

Has anyone had experience with Code C0306? I did a little research but I need to do more, but what I found so far is that I need to clean the ground wires that connect to the motor encoder.

 

[JPaul]

$1240? Did the new encoder motor come with a new transfer case attached to it?

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[Burtor]

Update: I installed the new TCCM. The problem still persists.

So I looked a the invoice of when I took it to the Chevy dealer. They told me that the motor encoder and TCCM had to be replaced, this is verbatim what the invoice said:

Customer states vehicle will not move when turning RT or left
When running towed in
Code C0306. Unknown 4WD position control
Encoder motor shorted or grounded in control - necessary to
Replace encoder motor and transfer case control module
$1240.00

Has anyone had experience with Code C0306? I did a little research but I need to do more, but what I found so far is that I need to clean the ground wires that connect to the motor encoder.

So the problem is not the TCCM.
Here's a link where a guy in Japan has a similar problem, except he's driving an H2
http://www.elcovaforums.com/forums/showthread.php?t=37819
He fixed it just by replacing his encoder motor. Generally the message means there was something wrong with your encoder motor at one point or another.

Run these troubleshooting tests before you get back to us, or take it into the shop. They'll be able to open it up and perhaps fix the assembly within the transfer case, which Mb30sdl suggested may be the issue, and sounds likely at this point.

Don't do any of these on a hill. You can run yourself over. Use the parking brake

1) (extremely easy, 5 minutes to complete) Lift one of the front wheels off the ground using the jack stand that's hidden inside your rear tailgate with the parking brake on and while the vehicle is in neutral. Try to spin it. If it spins freely, then you are in 4HI unlocked. If it does not spin, then you likely are in a locked mode. From what you describe I expect it to not spin freely.

2) (regular easy, 30 minutes to complete) Scoot under the your H3 with a 10mm socket and wrench to remove the 4 bolts holding the encoder motor on. While it is still plugged in with the parking brake on and the vehicle in neutral, press the buttons on your dash to see if it is moving to each distinct position. If it moves to each distinct position then there's probably nothing wrong with your dash buttons, TCCM, or encoder motor. This I also expect you to find. Put it back on. Don't drive through mud holes if you didn't put new rtv sealant on it before reinstalling.

3) (how to make your H3 drivable before you take it to the shop aka: do what 4speed says ) Get back under the car with another wrench and remove the front driveshaft. Here's a YouTube video of a generic driveshaft removal. It will be similar. The H3 has tons of ground clearance and most people fit underneath easily. https://youtu.be/fcrnCe_nZR0 Assuming the transfer case is stuck in a locked mode, this will allow you to drive the truck around in 2wd until you can get it to the shop to be fixed properly.

The reason that step three is recommended is that you do not want to be driving around on pavement with the transfer case locked. It causes extra stress on your drivetrain because the wheels have such good traction on pavement and can't slip to make up for the slight difference in speed. The worst case would probably be a long sweeping turn at highway speeds. I would expect something expensive to make a loud popping noise and stop working.

Good luck.

 

[tslevin95]

Did the 3rd option. Removed the front drive shaft and its driving fine and the turning problem is gone. But what does this mean?

 

[cgalpha08]

Did the 3rd option. Removed the front drive shaft and its driving fine and the turning problem is gone. But what does this mean?

Probably means something is wrong in your front diff/axle assembly. I would suggest opening the diff up and looking inside.

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[tslevin95]

Probably means something is wrong in your front diff/axle assembly. I would suggest opening the diff up and looking inside.

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How do I go about doing that? I have no experience with front differentials

 

[cgalpha08]

How do I go about doing that? I have no experience with front differentials

Easiest is to drain it and take the cover off. Then you can look at the fluid, see if it has metal in it. Remove the drain plug and examine that, it's magnetic so metal shavings will stick to it. Then remove the cover and see if there is anything obvious that's wrong.

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[Mb30sdl]

Or with no front driveshuft your TC is not in locked position snymore and spins feely. This my opinion due to prior experience with same problem after my TC was rebuilt first time.

 

[tslevin95]

Update: the mechanic at the other shop took a look at the front axel and transfer case. The problem is internally in the transfer case. He wanted $2,200 to open it and replace whatever is wrong. Since the problem is gone with the front drive shaft removed, I'm going to leave it off and just have it in 2-wheel drive for the time being, already seen an increase in gas mileage. Eventually will have to pay the $2,200 to have it finally fixed since winter is coming up.

 

[Burtor]

Good news, you now can justify youself a $2,200 budget for a toolbox full of all the things you would need to fix your car. Then, the nice part is that you get to keep the tools and the knowledge gained about rebuilding transfer cases afterward.

Another good option is that you now have confirmation that the first place screwed up somehow, and you have social license to to in there and start yelling at people until the fix it for free.
What are they going to do? Say no and tell you to never come back? I'm pretty sure that after the apparently terrible job they did the first time that you're already never going to go back there, so go for it.

My favorite option is still option 1. There's a lot of satisfaction and value in doing your own work. What's honestly the worst thing that could go wrong if you decide to tear it apart and work on your transfer case yourself? You break it... more? It's already technically broken, and if you get in too deep you know that there's a mechanic who has promised to charge you practically the cost of an entirely new one to look into it.

I say go for it someday, and be sure to report back with plenty of pictures and list the torque specs and sealants and other pro-tips you've learned by doing it.