SOLVED! New TC Motor... Could it be a dud?

[AC75TB07]

Just got in a new transfer case motor and it seems like a dud... won't even try to engage?

Is this something that happens?

It wasn't OEM. Just aftermarket. Perhaps a Dorman, but not sure exactly as it was the only one my garage could source new in a reasonable amount of time.

I've got a used OEM on the way, so I guess that will tell the tale for sure, but just wondering if this kinda stuff happens much at all?

I just bolted it on and plugged it in. Should I have done anything special during the installation? I pulled the ATC fuse first and my TCCM is a used known replacement as I thought that was my problem when the 4x4 started acting like a dick.

 

[mrrsm]

Pull the Power Connector... Check the Pin Outs within vs. the OEM Wiring Diagram and Check them for Powers via a Decent DMM and Grounds with a Light Probe or a Loaded Lighted Circuit Tester with the (KOEO):

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SOLVED! - 03 Escalade needs help

Good evening from Ottawa hot hot hot... Ok have a sorry 03 Escalade with a no start no crank problem. Now if I try 10 times, 1 time it might start and run for 5 min, no probs, no codes, however most times no crank no start. Now it is very rustyunderneath and coming home months ago from Ottawa I...

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[azswiss]

Did you check to see if the problem is mechanical? Can you shift the linkage manually (if the TC motor is unbolted)?

Are any codes being thrown?

 

[TJBaker57]

Just got in a new transfer case motor and it seems like a dud... won't even try to engage?

Is this something that happens?

It wasn't OEM. Just aftermarket. Perhaps a Dorman, but not sure exactly as it was the only one my garage could source new in a reasonable amount of time.

I've got a used OEM on the way, so I guess that will tell the tale for sure, but just wondering if this kinda stuff happens much at all?

I just bolted it on and plugged it in. Should I have done anything special during the installation? I pulled the ATC fuse first and my TCCM is a used known replacement as I thought that was my problem when the 4x4 started acting like a dick.

#1 Do the indicator lights come on breifly at key on?

#2 Is there an indicator light on at the mode switch for the current mode?

#3 Does an indicator light flash at the position you turn the switch to?

#4 Is there a service 4wd light on?

$5 Does the Service 4WD lamp light at key on for a couple of seconds?

 

[AC75TB07]

Did you check to see if the problem is mechanical? Can you shift the linkage manually (if the TC motor is unbolted)?

Are any codes being thrown?

The TC can be shifted manually, yeah. I had the codes read a while back at the dealership and they guy said it was the TC motor. I only had the check done and he brought the motor in and explained how it was failed. He bolted it back on and I went to my regular place once I knew what was wrong. They also put it on their scanner and came to the same conclusion. So I got the aftermarket replacement.

#1 Do the indicator lights come on breifly at key on?

#2 Is there an indicator light on at the mode switch for the current mode?

#3 Does an indicator light flash at the position you turn the switch to?

#4 Is there a service 4wd light on?

$5 Does the Service 4WD lamp light at key on for a couple of seconds?

1. Yes. All flash. Then all out.

2. Nope. All dark. Initially they would change occasionally if you could get it to shift. A couple times I got it to 4HI and they light would stay on if I switched back to 2HI. Didn't last long like that before it was totally unresponsive.

3. No. Nothing beyond initial start-up flash.

4. Yes. Dash light is on. The few times I was able to get it switch modes the light would stay off for maybe 15 minutes. Then the switch light would go dark and the dash light would illuminate.

5. You mean before the engine is started? I'm not 100% sure...Truck is at my garage now waiting for the replacement TC motor to arrive so I can't check.

What does it mean either way?

 

[TJBaker57]

The TC can be shifted manually, yeah. I had the codes read a while back at the dealership and they guy said it was the TC motor. I only had the check done and he brought the motor in and explained how it was failed. He bolted it back on and I went to my regular place once I knew what was wrong. They also put it on their scanner and came to the same conclusion. So I got the aftermarket replacement.



1. Yes. All flash. Then all out.

2. Nope. All dark. Initially they would change occasionally if you could get it to shift. A couple times I got it to 4HI and they light would stay on if I switched back to 2HI. Didn't last long like that before it was totally unresponsive.

3. No. Nothing beyond initial start-up flash.

4. Yes. Dash light is on. The few times I was able to get it switch modes the light would stay off for maybe 15 minutes. Then the switch light would go dark and the dash light would illuminate.

5. You mean before the engine is started? I'm not 100% sure...Truck is at my garage now waiting for the replacement TC motor to arrive so I can't check.

What does it mean either way?

#5 was just to prove that the service light worked in case it was not on.

#1 "All flash then all out" means there is a trouble code that causes the TCCM to disable all shifting of the 4wd system.
These are some.of the possibilities.

B2725 Mode Switch
C0306 Motor A or B circuit
C0321 Lock circuit
C0550 ECU malfunction

Since you just replaced the shift motor the mode switch would be the next guess.

You can try removing the ATC fuse in the underhood fuseblock for a minute or so to reset the TCCM. Chances are the trouble code will come back soon if it does reset at all.

 

[mrrsm]

Another GM-Under-The-Vehicle Pin Probe Diagnostic Video that includes Bench Testing the TC Motor. Note the Broken and Green Corroded TC Motor Harness Wiring:

 

[Mooseman]

With ignition off, You could try just moving the switch a lot back and forth to clean out the contacts. Some have had success with that.

 

[AC75TB07]

#5 was just to prove that the service light worked in case it was not on.

#1 "All flash then all out" means there is a trouble code that causes the TCCM to disable all shifting of the 4wd system.
These are some.of the possibilities.

B2725 Mode Switch
C0306 Motor A or B circuit
C0321 Lock circuit
C0550 ECU malfunction

Since you just replaced the shift motor the mode switch would be the next guess.

You can try removing the ATC fuse in the underhood fuseblock for a minute or so to reset the TCCM. Chances are the trouble code will come back soon if it does reset at all.

With ignition off, You could try just moving the switch a lot back and forth to clean out the contacts. Some have had success with that.

I did the back and forth with the switch a million times to be sure it was OK. Truly, I dont think it's that as when this trouble started, before the all lights out happened, you could move the switch to any position and it would illuminate the setting without issue, until you couldn't get any setting to illuminate at all...

I mean, I'm not ruling it out as a next step, but it would be a bit odd to have all settings on the switch do what they should (according to the changes in the lights, regardless if the shift occured or not) and then all out in one go? Wouldn't it? ...

I went back over my stuff and the shift motor was branded "APremium" ...

 

[TJBaker57]

mean, I'm not ruling it out as a next step, but it would be a bit odd to have all settings on the switch do what they should (according to the changes in the lights, regardless if the shift occured or not) and then all out in one go? Wouldn't it? ...

Remember this.... The switch itself does NOT operate the indicator lights. The indicator lights are wired back to the TCCM and only the TCCM controls what indicator light illuminates.

So if an indicator light is on this means that the TCCM has received a voltage from the range position sensor indicating the shift motor is in the position illuminated at the switch.

If a shift is in progress then the TCCM will flash the indicator light at the position that the switch is requesting.

If the requested shift is completed the light will turn on solid at the requested position.

If the shift fails then the TCCM will light the indicator back where it was when the shift was requested, not at the actual switch position.

 

[TJBaker57]

I did the back and forth with the switch a million times to be sure it was OK. Truly, I dont think it's that as when this trouble started, before the all lights out happened, you could move the switch to any position and it would illuminate the setting without issue, until you couldn't get any setting to illuminate at all...

I mean, I'm not ruling it out as a next step, but it would be a bit odd to have all settings on the switch do what they should (according to the changes in the lights, regardless if the shift occured or not) and then all out in one go? Wouldn't it? ...

I went back over my stuff and the shift motor was branded "APremium" ...

The only real way to know what is happening is to read the codes from the TCCM.

 

[AC75TB07]

Well, like I said, the motor was what the dealership told me when they ran their scanner. I assume if there had been more they would have told me... but I guess you never know. If the replacement OEM motor is s fail, I'll have to try another approach...

 

[TJBaker57]

Well, like I said, the motor was what the dealership told me when they ran their scanner.

This is the thing... There is no code that says the shift motor is bad. There just isn't. So anytime someone says they got a code that says the shift motor is bad it tells me they either don't want to properly diagnose the issue, or they don't know how. Doesn't matter if it is at a dealership or a bloke working in his driveway.

 

[AC75TB07]

Yes, that is true. I looked through the service manual and the codes available and saw there wasn't an exact "THIS IS IT!" code. I can only hope that the GM guy knew what was up. Could have been his first day for all I know...😲

 

[budwich]

One question... in your previous thread on this area about trying to get the replacement TC motor on... how did you resolve this problem? Is that now the "root cause" for this newest "saga"?

 

[AC75TB07]

One question... in your previous thread on this area about trying to get the replacement TC motor on... how did you resolve this problem? Is that now the "root cause" for this newest "saga"?

I watched a couple YouTube videos and read through loads of posts and found that you could move it with a pair of pliers or channel locks. Once I knew what to do it's pretty easy to shift.

 

[budwich]

So you never powered up the TC motor when it was not physcially connected to transfer case.

A basic resistant check with a meter on the motor across a couple of pin combinations will tell you IF the motor has the "basic capabilities" to function (ie. turn and have some reading of position).

 

[AC75TB07]

I didn't on my own no, but the place I go for repairs told me they tested it and it wasn't working properly... I can't say if that meant it did nothing at all, or what, but they did recommend trying to source an OEM part as they've had a few aftermarket TC motors for GM trucks be problematic right out the box...

 

[AC75TB07]

Thought I should add an update...

A used/replacement TC motor fixed everything! The aftermarket one was the problem all along. So, sometimes used is a good choice.

 

[Mooseman]

NEW= Never Ever Worked

Just because it's new doesn't mean it's good. Glad you found it.