Hi I I recently bought a 04 Hummer H2With 173k milesWondering about how the front end is supposed to act in 4Hi unlocked seems like I can put it in 4low and flat haul but in 4Hi locked or unlockedIt seems like it take quite a bit of gas pedal to get the thing to move also when turning even in 4hi unlocked it acts like it's still 4 high locked a little bit of binding in the front end as I try to make a turn even if it's not very sharpCould the front differential be locked in and not unlocking I have tried putting the thing in reverse I'm trying to back up a little bit with no success also once I get moving turning is not an issue and things seem to be more normal once I'm going down the road but from a dead stop or super slow it seems to be a problem

 

This isn't an issue with the front end likely, there is no front locking differential, or even locking hubs for that matter. If the center diff is stuck in 4hi locked that could be the issue. Are there any lights on the dash? Do the 4wd selector switches light up? Often the actuator can become stuck locked. try cycling 20-30 times from 4hi to 4hi locked and back and see what that does.

Because it seems to be working fine at speed, it could be a failing hydroboost. With a failing hydro boost brake booster, when turning sharp, it can cause the brakes to lock up since its plumbed inline with the power steering, making it hard to make sharp turns. I actually learned about this a week ago on the forum.

On dry pavement, do the front wheels seem to hop or skip or jump around? If so, its likely stuck in 4wd or the rear diff is stuck locked. If it turns smoothly, but with difficulty, it's likely the hydroboost.

 

Thanks for the response yes does seem to hop/ skip a little bit I've been real careful when making turns for that reason definitely seems like stuck in four wheel drive locked will try the 20 to 30 time switching back and forth no lights on dash saying service four wheel drive the light for 4Wd do light up when switching i do hear the motor turning on the transfer case the only time I hear more audible click though is when I go into four low and then back to 4 high or four high unlockedI haven't checked the transfer case fluid yet truck has been sitting a while

 

On mine, when the hydroboost failed (the second time 6 months after I rebuilt it), when sitting idling, if I turned the steering wheel, I could see the brake pedal physically move down some and apply the brakes (could also feel it if I had my foot resting lightly on the brake pedal).

If that is happening then it is the hydroboost failing internally.

Could very well be the transfer case stuck in 4hi lock as well.

 

Only hearing an audible click going into 4lo is normal. Try going into 4lo and locking/unlocking the rear diff and moving forward and back, many times as well. That could be stuck. If not, might have to get the T-case looked at. I know there used to be an issue with plastic shift forks melting in some years, but I don't remember which.

 

I had a similar issue with my 08. When I bought it the dealership replaced the shift actuator, but at times it wouldn't want to leave 4LO.

It did eventually pop out after driving for a bit, or reversing. Since it would eventually pop out, I thought maybe it just needed to be worked. So on gravel, I put it in 4LO, drove a bit, back to 4HI, drove or reversed until it released. Did this over and over and over, and eventually it seemed to start working normally. After probably 2 dozen times of that, it is just fine.

 

Will give this a go just replaced the starter so I can continue working through its quirks hopefully it's nothing major like transfer case forks I keep hearing about

 

Will check for this but to me it seems more like 4x4 lock

 

Hey apologize for a late response but did take it to a shop and confirmed it did have plastic fork 🤷 thanks GM it has been rebuilt with NOT plastic fork and has been doing it's thing. about $1200 parts and labor