I'm pretty sure I have a hub slowly dying.

2 months ago I was driving at low speed in 2WD (as usual) and all of a sudden it felt like my front driver wheel locked up. Pulled over and heard this loud hissing noise. Turned it off and back on and heard some hissing, but wheel turned freely. Cautiously went home. Hi/Low lights flashed. By the time I got home, no hissing. Next day, my lights quit flashing. Few days later, I tested the 4WD and it engaged no problem. Thought it was gremlins.

Yesterday, I turn my truck on and getting ready to head out and hear some clicking. My switch was in 2WD, but it sounded like it was trying to engage into 4WD. After a bit, my lights start flashing. Later in the afternoon, I have my window down trying to hear some hissing, but I hear a faint squeaking in relation to my speed. Hit the brakes, no change, squeaks just the same.

Now, it clicks every time I start the truck like it is trying to get into 4WD, and then my lights flash. I do not hear any hissing.

Would a loss of vacuum up front have anything to do with the 4WD system trying to engage while the switch is in 2WD??

 

the flashing lights usually mean the control unit is bad

 

I searched before and it sounds like if there is anything wrong to the point it won't engage, they flash.

 

yeah pretty much but a loss of vacuum wont be your answer

 

Clean or replace your shift motor.

It will flash the lights if its in between shifts. It is also possible the wiring is damaged.

There is no control module per say. Its functions are controlled by the GEM, it also does int light, wipers, auto down driver window, and accessory delay. If you only having a 4wd issue im leaning towards the motor or its wiring.

Servicing A Transfer Case Shift Motor

If yours has the brown wire you need to pull it out of the connector to get the motor out of the truck.

 

Int lights and wipers work. Today must have been a good day...all worked as advertised. I'll read through the cleaning procedures and check out the wiring.