4x4 PROBLEM ....... bad encoder motor?

[Supreme Pizza]

2003 Suburban 1500 5.3 4x4 automatic 

 

  Note: has leaking front diff seals. 

 

   When the vehicle is warmed up and the weather is good the 4x4 either works perfectly. Or, after selecting a few different ranges, the transfer case will lock into 2x4 mode, and the "service 4x4" message reads on the dash. Also, when that message is displayed, pressing any of the 4x4 options will not work at all, not even blinking lights on the selected range. 

 

   When the engine is cold, and its raining or low temperatures outside, the 4x4 does not work correctly. If you put it in 4 low, automatic 4x4, or 4 low, the vehicle acts very odd. When you put it in drive, and press the accelerator here is what happens: 

 

   Transmission seems to slip

   Vehicle acts as though the brakes are on

   Vehicle lurches forward but wont "drive". 

   Engine stalls if the you give it a lot of gas and let off. 

 

 

    Electrical?

    Wrong fluid in transfer case? 

    Bad encoder motor? 

    Problem with front diff? 

    Front axle in 4 low, and rear axle in 4 hi? 

 

    Any ideas? 

 

    Any questions about the symptoms? 

 

   

               Thanks guys. 

 

  

 

   

[Supreme Pizza]

Bad switch in the dash? Bad encoder motor? 

[Supreme Pizza]

OK, well i'm replacing the dash switch ($20 on for a new one on Amazon). 

 

If that doesn't work, I will replace the encoder motor ($25 used). 

 

Not sure whats wrong with the truck's 4x4 system, but I can replace the entire drive system for what a repair shop would charge just to look at the vehicle..... so be it. Time to throw some parts around. 

 

 

[swathdiver]

Why not hook the truck up to a Tech2 and find out in seconds what is wrong with it???  An advanced scan tool is as important as a set or wrenches and sockets for without it, one may lose precious time and hard-earned money trying to find out the hard way.

[Supreme Pizza]

Per your advise, I looked into it a little. It seems that the Tech2 is very specific to year/make/model. A specific set of years and models, as opposed to being universal like my OBD2 scanners that work on all rigs 1996 and up. Another problem is that they want almost $300 the Tech2 - I can replace the 4x4 switch, encoder motor, transfer case, front and rear diffs, and the wiring for less than $150. So the cost vs benefit doesn't seem to be there on that scan tool. Do you have more info on it? Am I missing anything? 

 

    

[swathdiver]

Well, the Tech2 is not a one time use tool.  You'd use it for this repair and for many many more.  If your scan tools can see all the functions of the 4WD system, what are they telling you?

[Supreme Pizza]

The vehicle is not showing any OBD2 codes. 

[Supreme Pizza]

4x4 switch was bad. $20 on Amazon.