anybody have a clue on these

 

You have TWO vacuum lines running from the back drivers side of the intake manifold behind the throttle body. It could be the ABS sensor but do you have a ABS light on or a CEL on?

 

I think It has to do with the speed sensor. My problem seems to have begun after I changed the driver's side hub.

 

You never got this fixed?..lol

Well, the driverside Hub is the one that has the Speed Sensor located in it. If there's dirt in there or it's not seated properly, it could be having trouble reading the teeth on revolution and can be casuing your engagement failures.

 

Mine sometimes works and sometimes doesn't. I have also noticed that if the cruise is working, it will turn off below 30 MPH, which I don't recall it doing before I replaced the sensor. Had a buddy scam the PCM with his professional scanner and he said it was showing an intermitent speed sensor signal. I was thinking if the hub sensor was bad, wouldn't my ABS light be on? I think am going to take the sensor and clean it really well and see if that fixes it. Also, We haven't had rain in 9 months, so I havent really needed 4WD.

 

This is most likely the problem for both of you, especially the guy that changed his hub recently. The ABS sensor regulates the cruise control, and I wouldn't be surprised at all if it was involved in 4wd engagement either.

Check the ABS sensor connection and then run a finger up and down the wiring as far as you can reach feeling for rough spots. It could have gotten pinched by something when the new hub went on, or it could have just been hit with some road debris and gotten scarred. If it is the problem, I THINK you will (unfortunately) need another new hub with the wiring. There are different part numbers depending on year and options, so make sure you find the one that's right for your truck. I can find the sensor itself, but if it's the wire, I think you need a whole hub assembly because it's sealed going through the hub. I could be wrong though.