Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

1 - 12 of 12 Posts

·
Registered
2008 chevy trailblazer_lt
Joined
·
3 Posts
Discussion Starter #1
Hi folks,
I have been troubleshooting my 4x4 not engaging and in the process of replacing the transfer case encoder motor on my 08 trailblazer, but hit a snag I need some help with. The problem is that the shaft alignment is off on the one being installed, as a result, it will not bolt up. Attached are pictures of the original one I removed and the replacement I was trying to install. I would appreciate some guidance on how to correct the alignment.

Thanks
David
 

Attachments

·
Registered
2004 gmc envoy_slt
Joined
·
2,529 Posts
Just align the TC mating spline shaft, using a pair of pliers, to match the encoder side. When everything is re-assembled and operated, it will work properly.
 

·
Registered
2002 gmc envoy_sle_xl
Joined
·
13 Posts
Just align the TC mating spline shaft, using a pair of pliers, to match the encoder side. When everything is re-assembled and operated, it will work properly.
Ok, I tried this. The only way that the shaft seemed to move (with a good bit of force) was counter clockwise. This was also the direction closest to where the motor spline was. So I started turning until I heard a pop and the splined shaft become somewhat loose. I stopped there as I did not want to screw any up if I haven't already.
Before, the light on the switch would stay solid on 2wd now it flashes in every position and nothing changes. And have a service 4wd light on. Currently, have battery disconnected hoping something will reset.

Am I screwed?
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
806 Posts
Ok, I tried this. The only way that the shaft seemed to move (with a good bit of force) was counter clockwise. This was also the direction closest to where the motor spline was. So I started turning until I heard a pop and the splined shaft become somewhat loose. I stopped there as I did not want to screw any up if I haven't already.
Before, the light on the switch would stay solid on 2wd now it flashes in every position and nothing changes. And have a service 4wd light on. Currently, have battery disconnected hoping something will reset.

Am I screwed?
Is the assembly all back together now? I mean when the indicator lights flash, is this with everything put back together? Also, did you reset the TCCM by removing the fuse yet?
 

·
Registered
2002 gmc envoy_sle_xl
Joined
·
13 Posts
Is the assembly all back together now? I mean when the indicator lights flash, is this with everything put back together? Also, did you reset the TCCM by removing the fuse yet?
The assembly is all back together now. when I first assembled the The transfer motor would not run when I turned the switch (reset via battery disconnect). I disassembled and got back on the spline with plyers with a lot of force it popped back into place and the spline no longer wobbled in the transfer case and I reassembled. Now the TC motor sounds like it is turning and changing but the differential motor is no longer running.

Prior to disassembly I had an intermittent problem with the transfer case motor working. The differential motor was working. I remover the Transfer case motor and disassembled. I found 2 of the magnets broken. I glued back in place with CA and reassembled the TC motor and not thinking plugged it in and changed the switch to test the motor (I have a new one on order). I wanted to test the whole system to see if there was anything else wrong and that is when I noticed the spline off and read this post.

Vehicle does drive and is not in 4wd.
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
806 Posts
So when the indicator lights are flashing that means the TCCM is attempting to move the shift motor to the position selected. The only way it knows what position the motor is in is by reading the voltage being returned by the encoder ring inside the shift motor. This would be the round plastic sensor with 3 wires connected to it that you should have seen when you had the shift motor taken apart. There are no range position sensors inside the transfer case itself, only that encoder ring inside the shift motor. So if the lights just keep flashing and never go solid at the selected position either the shift motor is not turning or the sensor is failing, or has failed, and the return voltage that it sends back to the TCCM never stabilises at the desired shift position. When the TCCM senses that a shift has failed it normally resets back to whatever position it was previously in and stops flashing the light.
 

·
Registered
2002 gmc envoy_sle_xl
Joined
·
13 Posts
So when the indicator lights are flashing that means the TCCM is attempting to move the shift motor to the position selected. The only way it knows what position the motor is in is by reading the voltage being returned by the encoder ring inside the shift motor. This would be the round plastic sensor with 3 wires connected to it that you should have seen when you had the shift motor taken apart. There are no range position sensors inside the transfer case itself, only that encoder ring inside the shift motor. So if the lights just keep flashing and never go solid at the selected position either the shift motor is not turning or the sensor is failing, or has failed, and the return voltage that it sends back to the TCCM never stabilises at the desired shift position. When the TCCM senses that a shift has failed it normally resets back to whatever position it was previously in and stops flashing the light.
I can hear the motor run and attempt to shift it. What now worries me is that the diffential motor that had been running prior is no longer running... That one would run before wether the TCmotor ran or not. I guess I am at the wait point. New motor should be here next week. Sort of wish i had bought it local.
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
806 Posts
What now worries me is that the diffential motor that had been running prior is no longer running... That one would run before wether the TCmotor ran or not.

Have you checked the fuse for the front axle disconnect? That disconnect actuator for the front axle has a different fuse than the Transfer Case fuse. One is in the underhood fuseblock and the other is in the rear fuseblock under the back seat.
 

·
Registered
2002 gmc envoy_sle_xl
Joined
·
13 Posts
Have you checked the fuse for the front axle disconnect? That disconnect actuator for the front axle has a different fuse than the Transfer Case fuse. One is in the underhood fuseblock and the other is in the rear fuseblock under the back seat.
I have not. Don't see why it would have blown in the 1 hour of me doing this but I will give it a look. Any idea which one it is in case I can't find it in a google search?
 

·
Registered
2002 chevy trailblazer_lt
Joined
·
806 Posts
Don't see why it would have blown in the 1 hour of me doing this but I will give it a look

I can't say either. But that's just the routine I use to diagnose anything.

Check with a meter, NOT by eye. Step 1: does it have power? Step 2: does it have ground? Then I move on to the control system, does it get the proper signal from the controller?

I am fairly certain it is marked "4WD" on the legend inside the fuseblock cover.
 

·
Registered
2002 gmc envoy_sle_xl
Joined
·
13 Posts
I can't say either. But that's just the routine I use to diagnose anything.

Check with a meter, NOT by eye. Step 1: does it have power? Step 2: does it have ground? Then I move on to the control system, does it get the proper signal from the controller?

I am fairly certain it is marked "4WD" on the legend inside the fuseblock cover.
Ok, well, like I said. Prior to pulling the TC motor the diff motor was working. I likely will do all that when the new tv motor comes in.

I do know that there is now svc 4wd when first started. It is only after driving it for 15 20 minutes that it comes on.
 
1 - 12 of 12 Posts
Top