I read thru a thread about this problem on the h3 forum - and my '05 H2 is doing the exact same thing... Intermittantly "engaging" 4Hi Lock when backing out of driveway, or sometimes when first starting out in drive moving forward, but almost always only with wheels turned either left or right.

I'm fairly savvy about the truck's functions and am an avid off roader (it is not accidentally in 4Hi lock) - it seems to break free after backing up, then rolling forward a couple times, but it is driving me nuts.

The H3 thread focused mostly on a plastic mode fork in the TC. Does the 2005 H2 have the same issue / part? Anyone have a DIY breakdown for the H2 transfer case?

 

Is the lock indicator light actually lighting up? Or you are just feeling some unusual resistance thinking the rear end is spooled?

I've attached the diagram and description for that rear diff circuit and basic control description of the transfercase.

Because you indicated this happens when you turn the wheels, are you sure everything in your front end is tight?

 

Sorry - I should have been more clear - the front wheels seem to bind up as if it were in Hi Lock (or 4Lo Lock) when it is not. I can switch to 4 Hi or Lo Lock with the buttons and hear them lock in. When I switch back to drive on surface streets, I can hear them disengage the lockers

It's when I first start driving away from a complete stop, and turn the wheels, that this occurs. Also seems to happen after the truck has set for a while, and almost always overnight, but occasionally, it is fine in the morning ???

The H3 thread said a plastic mode fork in the front transfer case was often to blame - Not sure if anyone has experienced this on the H2 - or if the '05 H2 even has this plastic part.

 

I'd jack the front end up, crank the wheel both ways and see if you have anything binding up in the drivetrain.

 

ive heard of this concern on the h2 also talked to gm tech would need new shift fork in transfer case binding up