4x4 works but pops out and buttons blink

[Duma]

My 98 yukon has the four button switch. My 4x4 wasn't working replaced the buttons new still didn't work. Replaced the transfer case shift motor still didn't work. Replaced front diff actuator still didn't work. Last thing iv replaced was the transfer case control module. Worked for about a day. Now when I hit the button to go in 4x4 it will only be in 4x4 for a short time maybe 1000-1500 feet then button starts to blink like it's not engaged. If my truck is warmed up it just won't go in 4x4. The transfer case is shifting and the actuator is engaging. I am at a loss at what the hell is wrong with it. Any help be good

 

[SunlitComet]

When the light blinks does it actually disengage 4wd or stay actively working. Have you verified both fuses are good?

 

[Duma]

When it starts to blink it Disengages. all fuses good I think it might be my front diff that's the problem. My 4x4 only works when truck is cold and only for a short time maybe 1-2 min or 1000 feet. All the parts I put on we're new nothing used. I have another front diff that I was gonna put in the yukon anyway. I can grab my front drivers axel and move it around.

 

[aj713]

What the hell could it be?! I thought gm 4wd systems were pritty much fail safe, atleast in the full size line.


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[Gzes]

They are when it's floor shift. That electronic shift is a nightmare when it acts up

 

[aj713]

I'm glad to have the floor shifter, too bad the truck is up for sale on Craig's list now.


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[Duma]

When summer hit that pos push button system is coming out and floor shift is going in. With a posilock conversion. Just need to get my 4x4 working for the rest of the winter. Nothing but ice and snow here in Nova Scotia

 

[SunlitComet]

Disengage as in just the front axle unlocks or you hear/feel the tcase switch to 2wd?

 

[Duma]

Think it's just the front diff that disengages

 

[SunlitComet]

Then I would suspect a dysfunctional actuator assembly or something in the engagement system in the axle that is having an issue. If the light starts blinking like you say then one of those two issues are it.

 

[Duma]

Front actuator was defective installed the orignal at kicked right no no problem. Napa gave me new actuator and some cash Back. Gonna run the old actuator till it dies

 

[SunlitComet]

Don't waist money with napa house brand stuff.

 

[Duma]

Don't waist money with napa house brand stuff.

Yup just learned that lesson