Which parts fail
Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2006 Hummer H3 owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact's husband owns a 2006 Hummer H3. The contact stated that while she was attempting to park the vehicle, the gear shifter seized in the neutral (N) position as she attempted to place the gear shifter into drive (D). There was no warning light illuminated. The contact was able to park the vehicle however, the gear shifter remained in the neutral (N) position. The dealer nor the manufacturer had yet to notified of the failure. The vehicle had yet to be serviced or diagnosed for the failure. The failure mileage was approximately 180,000.
I was driving the vehicle at a normal rate of speed and stopped at a traffic light getting ready to change. I applied the brakes and when doing so, I heard some horrible noises and felt certain that parts had fallen out of the car. I knew something was immediately seriously wrong. I put the car in park (but it was effort and a grinding noise to put it in park) and stepped out to look under the car. No parts were on the ground, but something was leaking out of the bottom of the car. I got back in and put the car in drive to move it from the roadway knowing I was going to need assistance to tow it somewhere. It grinded trying to put it in any gear and only "revved" the engine when I tried to apply gas to drive it. There was absolutely no warning. The tow driver immediately noticed the drive shaft was disconnected and that was the leaking and thus going nowhere. …
Tl* the contact owns a 2006 Hummer H3. While the vehicle was parked the contact noticed the HVAC unit failed. The vehicle was taken to the dealer for diagnostic testing and the technicians stated the HVAC blower motor over heated and melted the resistor. The technicians stated the blower motor, relay and the wiring harness needed to be replaced. The vehicle was not repaired. While driving the front drivers side mirror also began to vibrate and when depressing the accelerator pedal the vehicle would decelerate. The technician stated that the arm bracket that holds the front drivers side door mirror was broken and needed to be replaced. The vehicle was taken to the dealer where the electric pedal was replaced. The vehicle HVAC unit and the drivers side mirror were not repaired. The approximate failure mileage was 90,000.
Plastic shift fork in transfer case broke. Truck locked up turning onto main road from side street was almost hit.
I have two 2006 H3 hummers 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. …
Tl contact owns a 2006 Hummer H3. On May 23, 2008, while driving 35 MPH, the contact attempted to downshift and noticed that the transmission made a rubbling sound. The transmission stopped functioning and the vehicle suddenly pulled to the left. The vehicle was towed to a GMC dealer and they stated that the clutch assembly exploded. The vehicle was serviced and the contact did not notice any differences prior to the failure. While driving 55 MPH, the brake warning light illuminated on the instrument panel. The brake pedal extended to the floor when it was depressed. The contact had to downshift and apply the emergency brake to stop the vehicle. The vehicle was towed to the dealer and they stated that the brake line had cracked on both sides of the vehicle. The contact was not in a crash, but the vehicle was serviced for the failure. …
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...
Tl* the contact owned a 2006 Hummer H3. While driving 15-20 MPH the front drive shaft broke. He coasted to the side of the road. The vehicle was towed to an authorized dealer. He stated the dealer advised him that the front drive shaft needed replacing. The dealer refused to repair the vehicle because of the number of times the vehicle had come in for this failure. The contact stated he no longer owns the vehicle but feels its unsafe to be on the road. The failure mileage was 21,000 the current mileage was unknown.
Tl 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.
Tl* the contact owns a 2006 Hummer H3. While parked with the brake pedal depressed, the contact placed the gear shifter into drive but the vehicle would not accelerate. The vehicle was taken to the dealer for diagnostic testing. The technician advised that the plastic fork in the power train transfer case would have to be replaced with an upgraded version. The vehicle was repaired. The approximate failure mileage was 60,000.
Transmission complaints in other H3 years
Frequently asked questions
How common are transmission problems on the 2006 Hummer H3?
NHTSA has 20 complaints about the transmission & drivetrain of the 2006 Hummer H3, 6% of the model year's 362 complaints. The component named most often is driveline (3 mentions).
Is there a recall for 2006 Hummer H3 transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2006 Hummer H3, though it has 4 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2006 Hummer H3 transmission problems start?
Half of the complaints with a recorded mileage happened before about 60,000 miles, and 47% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to transmission & drivetrain problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.