'05 TB wheels locking up in 4HI

i drove to work today with my trailblazer set in 4HI because there was snow and considerable ice on the roads. When i left the office, the parking lot was still messy so i left it in 4HI and as i was backing out of my parking spot, i got maybe 3-4ft back and all the wheels locked up. I put it into drive thinking i must have accidentally hit the snowdrift next to the rear of the truck. When i pulled forward i made it perhaps 2ft and it froze up again. right before it froze up there was this slight grinding noise then the stop. I put it into park, switch down to 2wd. When i did this it "kicked" out, making this loud metallic clanking noise and lurched forward slightly. I left the parking lot and decided to get to a parking area that was free of cars and tried 4HI again. again it did the same thing. If the wheel is completely straight, i'm fine but the slightest turn of the wheel, even 5 degrees, it locks down again. you can feel the back-end hitched up a bit like the brakes were seizing. But the best way to describe the release when you put back into 2wd is as if you had a standard trans car on a STEEP hill with the emergency brake on. when you release the brake, you hear that metal pang and a lurch forward.
i did notice that when it first happened my 4HI light flashed a few times but it didn't do that in the 'testing' a few minutes later. i drove home in 2wd with no issues but at home i re-tested the 4wd and it did the same thing. I couldn't duplicate in auto-4wd and didn't try 4LO.

Does this sound familiar to anyone? could it be the transfer case? Hubs?

any and all thoughts would be greatly appreciated. Thanks and Merry Christmas.


btw, specs are 2005 Trailblazer with just under 45k, all same brand tires, brakes are fine, no other issues except my check engine light likes to flicker on here and there for a split second and go off. I've had the truck test at the dealership for this and nothing was found wrong.

Welcome to AF. If all 4 wheels have good traction the the hitching is normal, mine does that also, unless the pavement is very slippery, might try changing the transfer case fluid just for maintenace issues. Get it on an icy patch and see what happens, but I think you are good here.

Do not use ATF for the transfer case and use the special fluid from the dealer only,Auto Trak II.Get 3 quarts of it,takes about 2 and a half quarts

Welcome to AF. If all 4 wheels have good traction the the hitching is normal, mine does that also, unless the pavement is very slippery, might try changing the transfer case fluid just for maintenace issues. Get it on an icy patch and see what happens, but I think you are good here.


well, the way it is working now....i can't use 4HI at all. as soon as i activate it, if i turn the wheels at all, it locks down and i can't move, it's impossible to drive in a straight line the entire time. example if i try to pull out of my driveway, i have an issue, or navigate a slight curve. So in all essence, 4 wheel drive is useless and not operating. I have an appt with the dealership tomorrow morning since i live out in the country and use it frequently when it snows. I'll see what they say tomorrow and post back. Thank you for the advice.

I don't understand here, is this happening on dry pavement?

What did the Dealer say the problem was and what was the corrective action in solving the problem!