Stuck in 4WD

[swathdiver]

wsteele and Fless thanks very much for the replies. I think I am going to throw a TC encoder motor on it in the next week or so and see if that’s it. I know it’s a shot in the dark. Does anyone know for sure if the encoder motor needs a relearn procedure done on it for sure or not as wsteele mentioned? I have read that the TCCM requires it, but if you buy a Dorman unit it does a self calibration. The encoder motor however, I have not read about a procedure being needed. If it is needed, will this render the truck undrivable until it is completed? Any and all replies are welcomed and appreciated. Thanks again for all of the help.

Were you able to see all of post #2 including the photo with the procedure for diagnosis?

 

[UpAndDown]

Were you able to see all of post #2 including the photo with the procedure for diagnosis?

I was. Thank you for posting it. A lot of it is somewhat confusing to me though. I am going to take the foolish approach and shotgun the TC encoder motor assembly and see where that gets me. At worst, I will have a new part, which seems to be prone to failure anyways.

 

[UpAndDown]

Thanks again guys for all of the help. Reading up online has shown some people say a relearn is needed with the TCCM replacement, while others have said that holding the dial switch over in the N position for about 30 seconds will allow a relearn on the TCCM. As far as a relearn on the TC encoder motor itself, I haven’t seen anything other that what was posted here a few posts back from wsteele. If I can’t get the truck to go into N electrically before I swap the motor out, which way do I turn the sprocket or shaft, whatever is sticking out of the TC, and how do I know when I have reached the N position? Perhaps I should start a new thread specifically on the replacement of the TC encoder motor as it would probably catch people’s eyes that have done that swap where this one may not. Once again I am beyond appreciative for all of the help and information provided so far.

 

[wsteele]

I was. Thank you for posting it. A lot of it is somewhat confusing to me though. I am going to take the foolish approach and shotgun the TC encoder motor assembly and see where that gets me. At worst, I will have a new part, which seems to be prone to failure anyways.

If you are feeling particularly lucky (or just like options versus equity), it is possible to just replace the encoder (the position sensor), which is the part that most frequently fails, in the part that most frequently fails.

On the motor learn process, as best as I can tell from the sparse information I have found (google isn't as good as it used to be), it is about dialing tolerances. That is, getting the motor in the center of any tolerance build ups between the motor and the TC. I think if you can't get it to go into neutral before you start, simply turning the shaft so it is in neutral and installing the new motor will get you back on the road just fine (if it was the motor in the first place). Everything I have seen is the TCCM senses the motor position and displays that in the switch when power is applied.

As long as you get the new motor installed, it appears the old TCCM will see the position of the motor sensor and display it on the switch and that will also indicate the TC switch status as they are synched mechanically (which should be neutral as that is where the new motor will be set up).

If it doesn't display it when everything is installed, you know you didn't;t have a motor/encoder problem.

As far as what the shop manual indicates with regard to the relearn, refer to James' post #2. It calls for a relearn for either components replacement.

 

[Fless]

The TC probably has three positions -- just guessing -- so if you have no joy getting it into neutral electronically, for neutral turn the TC shaft (the one that the encoder motor would) to a setting so that the rear propshaft spins freely. You may have to rotate the propshaft slightly to be able to turn the small shift shaft, thereby taking tension off of the TC. First, though, if the encoder manufacturer specifies that the motor is shipped in the neutral position, all the better. You can match the position of the TC's keyed shaft with the motor position. That's probably the only way you'll get it mounted anyway.

I think if both the TC and the encoder motor are in the same mode (neutral, preferably, but I wouldn't turn the encoder motor while it's not mounted) then the TCCM is going to know that by what the encoder motor reports. It's a simple matter of the unique resistance of the motor's internal position sensor getting reported to the TCCM for the TCCM to figure out the mode, if that makes sense.

 

[Fless]

My responses have been based on earlier TC motors; however, yours doesn't connect the same way physically as I thought; it's a somewhat different interface. I'm not sure about all the talk about having to have it in neutral, etc. There's not a shaft on the TC, from what I can see. You'll need to do some further research on if the TC needs to be in neutral or if the motor does some kind of auto-sense.

 

[UpAndDown]

Fless and wsteele thank you both once again. Fless I see what you’re saying. There doesn’t appear to be a keyway on the pictures I’ve seen so the transfer case and the encoder motor appear to be able to be mated in any position. Hopefully the functional encoder will then tell the TCCM what position it is in. Am I off base here? Still may start another encoder motor replacement specific thread as there has to be a bunch of guys here who have swapped it out. As always, comments and suggestions are appreciated and welcomed.

 

[wsteele]

My responses have been based on earlier TC motors; however, yours doesn't connect the same way physically as I thought; it's a somewhat different interface. I'm not sure about all the talk about having to have it in neutral, etc. There's not a shaft on the TC, from what I can see. You'll need to do some further research on if the TC needs to be in neutral or if the motor does some kind of auto-sense.

View attachment 349113

I agree, I was looking at 07 parts (my model year) but it appears the 08’s are different.

Another approach to get the motor and TC synched, would be to connect the motor before bolting it down. Apply power and your switch will likely display neutral (or whatever the encoder says it is to the TCCM). Then select 4H on the switch (assuming you never got it in neutral before starting). This will position the motor to where your TC was before the old motor was removed and likely you will be synched.

With all those teeth, I can kind if see why learn might be needed.

 

[wsteele]

Found this video. No mention of having it in neutral before motor replacement. In the video, it looks like the position sensor might be a separate piece next to it.

 

[Fless]

I would recommend getting a subscription to AlldataDIY for your truck. Then you'll have access to all sorts of good info.

I saw that video too; strange that there's no mention of indexing or a learn procedure, if one is needed.