4wd Auto works but 4hi and 4lo doesnt

Tthompson · February 24, 2019

I just replaced the Transfer case encoder motor because it threw a code and my 4wd didnt work at all. Now only 4wd auto works and when i put it in 4hi it is like 2wd. When i select 4wd Low i can feel it in low gear but again it is like its in 2wd. Any suggestions? Thanks

Tthompson · March 26, 2019

Has nobody had this problem? So far ive replaced the transfer case motor, front actuator, and 4wd switch. The front actuator moves like it should in all modes but 4wd doesnt work still only in auto 4. Gm dealer wants me to put new transfer case motor or tccm in.

carnau · March 26, 2019

14 minutes ago, Tthompson said:

Has nobody had this problem? So far ive replaced the transfer case motor, front actuator, and 4wd switch. The front actuator moves like it should in all modes but 4wd doesnt work still only in auto 4. Gm dealer wants me to put new transfer case motor or tccm in.

Someone probably has. we need some more information please. What's the year/make/model? Does it have any codes in the vehicle? The TCCM is a transfer case control module. Before you just throw parts at it (which look's like what you have been doing lol) Let me try to help you Diag it. Get me that information. Quote me, so I get a message saying I need to check, and let me see what I can do to help.

Tthompson · March 26, 2019

8 minutes ago, carnau said:

Someone probably has. we need some more information please. What's the year/make/model? Does it have any codes in the vehicle? The TCCM is a transfer case control module. Before you just throw parts at it (which look's like what you have been doing lol) Let me try to help you Diag it. Get me that information. Quote me, so I get a message saying I need to check, and let me see what I can do to help.

It is a 2004 Chevrolet Silverado 1500 5.3 with the np246 transfer case. I had a code and that is why i needed a new transfer case motor. After installing that i have 0 4wd codes now.

carnau · March 27, 2019

1 hour ago, Tthompson said:

It is a 2004 Chevrolet Silverado 1500 5.3 with the np246 transfer case. I had a code and that is why i needed a new transfer case motor. After installing that i have 0 4wd codes now.

How are you getting the codes? When you took it to the dealership did they diagnose it and say it needed a TCCM or did they just tell you "That's what it could be?"

When you replaced the Encoder motor was it a new one or a rebuilt one?

Do you have a test light and/or a multimeter and are you comfortable doing testing?

The encoder motor wires use to like to lay one the front drive shaft and that would cause problems. Make sure they are not close to it. (just throwing this out there because of all that I have seen.)

Tthompson · March 27, 2019

19 minutes ago, carnau said:

How are you getting the codes? When you took it to the dealership did they diagnose it and say it needed a TCCM or did they just tell you "That's what it could be?"

When you replaced the Encoder motor was it a new one or a rebuilt one?

Do you have a test light and/or a multimeter and are you comfortable doing testing?

The encoder motor wires use to like to lay one the front drive shaft and that would cause problems. Make sure they are not close to it. (just throwing this out there because of all that I have seen.)

I have a scan tool that can read all of that.

I took it to the dealer today to diagnose it and they said it “could be” the encoder or the tccm but i didnt get to talk to the mechanic himself. They said to get a new encoder under warranty first. But i think the encoder is working properly because it sounds like it is and it runs through auto 4wd, 2wd, 4hi and 4lo like it should. And auto 4 works perfectly but in 4hi it is like 2hi and 4lo is like its in 2lo because the front tires dont spin but the actuator makes noise. I thought it was internal but that doesn’t explain why 4 auto works.

If the tccm was bad shouldnt it throw a code or not activate the encoder and actuator like it does.

I replaced the encoder with a brand new dorman one.

I made sure the wiring was fine.

And I know how to use a multimeter.

Thanks

Edited March 27, 2019 by Tthompson

carnau · March 27, 2019

18 hours ago, Tthompson said:

I have a scan tool that can read all of that.

I took it to the dealer today to diagnose it and they said it “could be” the encoder or the tccm but i didnt get to talk to the mechanic himself. They said to get a new encoder under warranty first. But i think the encoder is working properly because it sounds like it is and it runs through auto 4wd, 2wd, 4hi and 4lo like it should. And auto 4 works perfectly but in 4hi it is like 2hi and 4lo is like its in 2lo because the front tires dont spin but the actuator makes noise. I thought it was internal but that doesn’t explain why 4 auto works.

If the tccm was bad shouldnt it throw a code or not activate the encoder and actuator like it does.

I replaced the encoder with a brand new dorman one.

I made sure the wiring was fine.

And I know how to use a multimeter.

Thanks

One thing I have found about Dorman encoder motors is they are never timed correctly. That's probably the reason you're not getting a code. You can actually disassemble it and time it correctly and your problem will probably be resolved. On the inside of the encoder there is a gear with a dot on it. That gear has to be lined up with the case. Let me see if i can find you a video. See the TCCM doesnt know that it isn't aligned. It just knows the sensor is saying it is right. So that's why you don't have a code.

Here it is. Perfect video.

Tthompson · March 27, 2019

4 hours ago, carnau said:

One thing I have found about Dorman encoder motors is they are never timed correctly. That's probably the reason you're not getting a code. You can actually disassemble it and time it correctly and your problem will probably be resolved. On the inside of the encoder there is a gear with a dot on it. That gear has to be lined up with the case. Let me see if i can find you a video. See the TCCM doesnt know that it isn't aligned. It just knows the sensor is saying it is right. So that's why you don't have a code.

Here it is. Perfect video.

I went out and got a new encoder motor under warranty and put that one in and now it appears to be working now. Thank you for all your help

carnau · April 1, 2019

On 3/27/2019 at 7:56 PM, Tthompson said:

I went out and got a new encoder motor under warranty and put that one in and now it appears to be working now. Thank you for all your help

Glad it helped. I figured it was the encoder. Glad you got it fixed.

dtnel78 · April 1, 2019

Did you replace just the encoder motor or the "Transfer Case Shift Motor". Seems lost time the transfer case shift motor gets replaced unless one is into replacing just the encoder motor part. I always just replace the complete shift motor with the encoder in it. Less hassle.

Was your code a C0327 by chance?

Also if I recall correctly I believe you mentioned the Auto 4wd option? If so don't use Auto but rather 4hi or your 2wd unless you're using the 2wd for a particular reason.

The reason I state to not use the "Auto" is that's what my local transmission shop has recommended. He says that with the Auto there's a clutch pack in there and it wears out sooner than expected where if you're locked in 4 Hi then you're locked in. I just watch the road surface and if it goes dry I switch to 2wd and when slipper go to 4hi on the fly.

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