I have a 2006 Hummer H3 with app. 79,000 miles on it.. I was driving to work on the highway and halfway there, I started to get a really bad vibration and loud humming noise coming from the driveline. It starts at about 40 mph and comes and goes every few seconds. Its worse when I hit the gas pedal.. the universal joints have already been replaced due to cracked universal joints for some odd reason.. the top end of the engine had just been rebuilt 2 weeks ago as well due to sticking exhaust valves. This truck is babied and has never been off- road. Mainly highway miles only.. I just had it aligned. All the fluid levels are correct. All the driveshafts are tight and nothing seems to be loose.. no modifications have been done to it.. very unsafe to drive because something could lock up and make you lose control of vehicle.. this will be the 6th time I've had it in the shop for problems...

- Canton, OH, USA

The contact owns a 2006 Hummer H3. The contact was driving approximately 5 mph with the "four wheel high lock" in activation. When approaching a turn, the front wheels began to squeal. The reading on the instrument panel displayed the four wheel high range and no indication of the lock being engaged. The failure occurred whenever the vehicle was in operation. The failure will be diagnosed by an authorized dealer. The failure mileage was 90,000. The VIN was unavailable.

- Fairlfied, PA, USA

I have two 2006 H3 Hummer both with the 5 speed manual transmission. Upon acceleration from a stopped position in first gear, depressing the clutch for the shift into 2nd gear the engine rpms revs to about 4000 and stays there. Shifting into 2nd gear & releasing the clutch the rpms drop back down. Accelerating to about 3000-3500 rpms, depressing the clutch, again the rpms climb to around 4000 and stays there. The same thing occurs during up shifts... this has happened no less than 7 times on one H3 and 5 times on the other H3. The Hummer dealer can find no stored codes, and can not duplicate this. GM has been notified, but nothing has been done to repair this problem because the dealer can not supply defect codes. This has been going on since August '06 with no end in sight. I have asked the ECU be either reflashed or replaced and was told it was too costly to just put parts in without any codes. I believe the software could be corrupted. And is not aware anything is wrong. Thus there are no codes.

- North Prairie, WI, USA