Hello, I'm a new member here and just got an 07 H3 auto with the adventure package last Tuesday. Last night I was testing out the different 4x4 modes in a dirt field, when a problem came up. The transfer case shifted fine from 4 hi unlocked to 4 hi locked to 4 lo locked, then back through until it got to 4 hi unlocked. When it tried to shift back to 4 hi locked, it started making a grinding noise like someone who can't drive a manual. It would shift back into 4 hi locked and 4 lo locked just fine, but every time I try 4 hi unlocked, it makes that terrible grinding noise. I had to limp it home in 4 hi locked, but I kept it under 40 and kept the turning to a minimum. It has a 3 month warranty through the dealer I bought it from that covers the transfer case, but I wanted to ask here before I took it down there. I searched the forum and came across the TSB 3424 about the transfer case not completing shift but I havent found what the bulletin actually says. So any ideas or help from anyone would be greatly appreciated, thanks!

 

try this link and see if it helps u https://www.hummerforums.com/forum/s...ad.php?t=14671

 

Thanks, I read that thread during my search but it says nothing about a grinding sound from the transfer case. I'm guessing it has something to do with the shift fork not moving correctly.

 

I saw a post some where about the shift forks, I think it said early ones were plastic & prone to breaking. Sounds like it's time to try out that warranty!

 

I think I read that somewhere too. Thanks for the opinions on this, I really appreciate the help. If anyone has had a similar experience, please let me know. Its getting dropped off at the dealer Sunday night so they can start working on it Monday morning. Lets hope it doesnt take too long...