Help please! I have a 2006 hummer h3 and it has been driving great. All of a sudden last night while going a out 25 mph I heard a bunch of grinding noises and had no gears all of a sudden. I parked and let it sit for a while. I can move through 4hi/4hi lock/4lo lock with no issues on the dash. Still no gears in 4hi, but can switch to 4hi lock and it will drive. Will grind moving through any gear until it starts working fine in 4hi lock. No park in 4 hi normal. Plan on taking the transfer case off and opening it up, but trying to get some insight at the same time. Is this related to the plastic shift fork? Or is there a larger problem. No leaks coming from transfer case or front diff.

 

Grinding is not good. When was the last time the T Case fluid was changed?

 

It's been within a year

 

I have never had the plastic fork issue personally, but I do know plenty of others that have. I thought it either sifts into/out of lock or it won't, although some have said their T Case made strange noises before they figure that out.

 

Sounds to me more like a front end issue. Check CVs, intermediate shaft and R&P.

The H3 Tcase will not move the vehicle in 4HI unlocked if the front differential is damaged. It will sent 100% of the power to the front differential via the prop shaft (least resistance).
If the prop shaft spins in 4 HI unlocked your issue is in the differential.

In 4 HI LOCK the Tcase "locks" the front and rear portions of the Tcase and will propel the vehicle.

 

Going to investigate, thank you! Is fixing the differential a difficult job?

 

Depends on what is wrong. Whaen was the last time the diff lube was changed?

Drain it and open it op for a look to see if metal pieces are present or the gears look worn....

 

Yes lol, differential work is a pain in the azz especially regearing. Being the front differential housing is aluminum its susceptible to flexing.

 

check the front driveshaft. Could have broken teeth.

 

H3 front prop shafts have toophs? Please, show me where to look for the elusive driveshaft teeth... Are you talking about ring and pinion teeth?