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Pete
Pete, Automotive Mechanic
Category: Transmissions
Satisfied Customers: 27135
Experience:  GM and Mercedes vehicle technician.17 years experience.
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2004 gmc 1500 4x4, no 4x4, push 4x4 switch on the dash it

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2004 gmc 1500 4x4, no 4x4, push 4x4 switch on the dash it lights up actuator goes into gear on the front diff but no 4x4, when it's in 4x4 mode I can't turn the front drive shaft with the front wheels off the ground but as soon as I jack the back up and put the truck in drive the rear shaft turns but not the front, there is no power going through the transfer case, is this a screwed transfer case or maybe a transfer case switch problem ?

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

The most common cause with what you have described here is a fault with the transfer case actuator itself.This fails internally and causes this issue.There were some faults with the position sensor in the transfer case actuator where the actuator was removed and taken apart for inspection and the sensor replaced.GM had released a bulletin on replacing this sensor depending on what code was set.

What needs to be done from here is to have the codes read out with a compatible scan tool that will read the transfer case computer.Once this is done any codes set need diagnosed to help locate and repair this issue here.I suspect either the transfer case actuator sensor needing replaced,actuator itself or an internal mechanical fault in the transfer case needing removed and repaired or the transfer case replaced.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service,your 5 star rating is appreciated.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 4 months ago.
Are you thinking that the transfer case motor maybe shot ?
Customer: replied 4 months ago.
what about a fuse ?

If it was a fuse then the front diff wouldnt engage as well as they are all tied in together for operation here.This sounds more like the transfer case actuator itself needing replaced.This is very common.

I would have the transfer case codes checked to be sure.

Let me know if you need anything else and feel free to rate my help here as this is how I receive credit for my time.Your 5 star rating is appreciated

Thanks Pete

Customer: replied 4 months ago.
I just went out and checked, when I shift it into 4x4 I can here the front diff actuator engaging and the shift motor on the transfer case is engaging

If you can hear the motor on the transfer case engage and disengage then more then likely this is an issue in the transfer case itself mechanically.I have seen shift fork issues as well as damaged gears internally cause this here.I would still have the fault codes checked/read out to see what codes are set and then those codes diagnosed as this will help to make sure this is the cause here.It is still possible that even though the actuator on the transfer case is shifting that it is not shifting properly and may be the only issue needing replaced.

Thanks Pete

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