It looks like the section on the lower right hand corner is completely out?
If so, taking a drift/punch, and going on the right and left of it, and seeing if it will push in, and break the corrosion, is where you are at..
As I said, its been years since this has been an issue for me.. I suggest you post on the other forum about it, and get some more insight than my old and fuddled brain is remembering.
www.gmtnation.com
And post in this post maybe.. Or start your own referring to this post..
Hello to all the fellow GMT users on here. I am new to forums but think I have the gist of it. I have recently been having trouble with my 4x4 not engaging in my 2004 trailblazer. Switch it over to 4hi and the actuator and transfer case whirring sounds are present and the indicator light...
gmtnation.com
I am also on that forum with this same screen name, so if I can help there I will.
Not many on this forum have had this, because these full size trucks that this forum is about have a separate unit, whereas you and I have a integrated unit.