4wd not engaging, HELP!

I live in Alaska so it is extremely important for my 4wd to work.

97 yukon 2dr push button 4x4

Last night I was driving home and decided since the roads were pretty dry to switch to 2hi out of 4hi. I switched while driving about 35 mph(this is what I believe caused my 4wd to now not engage.)

Today I drove my car and switched it back into 4hi(lights right up). It didn't engage as my back wheels spun and no spinning up front. I try reverse into drive and nothing. When pushing the 4hi button, you can hear it trying to engage.

I drove around quite a bit pushing on the buttons, and when in 4hi(light on but not engaged) I switched to 2hi and there is a grinding noise.

I've been driving in 4hi for the past couple months and now it suddenly doesn't work! Help please

Have you tried from a stop in park or neutral? Then back up and go front a couple times til in 4?

Tried it, still doesnt engage 4hi.

Drove it around in 4hi for 15 mins to see if it would engage. Nothing.

When I click between 2hi and 4hi, the lights come on right away, there isnt any blinking. Does that mean the actuator is working?

Also what is the grinding sound I get when switching from 4hi to 2hi when I'm rolling? Its doing this grinding noise even though the 4wd isn't even engaged.

what should I look at if I crawl underneath my truck?


Are there vacuum hoses I should check? Wires I should check?

I have a manual transfer case but I remember seeing something about the motors going bad. Can you get into 4-low?

Ive never tried 4 low on this truck as it is just a DD. Proper procedure to get into 4 lo I believe is switching from 4hi into 4lo while in neutral while between 0-3mph.

If my 4hi light is on but the 4wd isnt actually engaged, can i still try switching to 4 lo?
What would switching into 4lo prove?

If the tcase motor was bad, wouldnt the 4hi light not stay illuminated and switch bacl to 2hi?

God said:

Ive never tried 4 low on this truck as it is just a DD. Proper procedure to get into 4 lo I believe is switching from 4hi into 4lo while in neutral while between 0-3mph.

If my 4hi light is on but the 4wd isnt actually engaged, can i still try switching to 4 lo?
What would switching into 4lo prove?

If the tcase motor was bad, wouldnt the 4hi light not stay illuminated and switch bacl to 2hi?

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You can switch into it from 2. I don't see any reason why you couldn't switch. My chevys that have had electronic transfer cases would blink if it couldn't get into 4 but those are nbs models.

I just put it in 4 lo but still no torque from the front. You can even hear what I think is the front driveshaft spinning, maybe I should check differential fluid levels

God said:

I just put it in 4 lo but still no torque from the front. You can even hear what I think is the front driveshaft spinning, maybe I should check differential fluid levels

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Yeah definitely check that and transfer case. If you can get it on jacks and try to see if you can see the driveshaft spinning.

If you see the DS spinning and your front wheels are not taking the power transferr you need to do some hub work. Your auto locks are worn.

Possible encoder motor. I was having similar problems. Or front actuator. Check to see if actuator moves, have partner press 4hi and watch actuator.