The vehicle transfer case has failed twice. The first failure occurred at 33,377 miles. The dealer repaired the vehicle under the vehicle original warranty. The second failure occurred with 43,971 miles. (miles per each transfer case)the vehicle was idling rough and in 4WD. I selected the AWD mode and the vehicle made a clunking sound but stopped idling rough. When I tried to put it back in 4WD it would not go into the 4WD mode. When I returned home I tried to put the vehicle in 4 low and it went into 4 low but would not come out of 4 low. The servicing dealer and GM claim the tc failure is because we live in a northern state and therefore use the AWD and 4WD more than other regions. I spoke with another dealer and they claim GM is aware of this problem, but cannot fix it. The second dealer said they could repair the vehicle, but assured me that the tc would fail again. Both dealer said they see these Trailblazer tc failing all winter long. There were about 4 to 5 Trailblazers in the service dept (not including ours) with broken transfer cases.

- Chugiak, AK, USA

Purchased 2003 Trailblazer in October 2003. Had problems shifting into 4WD in winter 2003-04. When switching into and 4-wd, lights would flash and it would remain in 2-wd. Service 4WD light came on soon after. Brought it to the dealer who could not replicate problem. This happened later the same year and also the following year, each time the dealer could not find a problem. This past weekend while on vacation, a parking valet for some odd reason, switched the car into 4-wd low. Car will not come out of 4-wd low. Had to leave at dealer 150 miles from home and rent a car to get home. I am waiting until after the 4th of July holiday for them to look at car and figure out problem.

- Malverne, NY, USA

Drove car to a friends. Had to park in the mud. Came out later to find that the 4WD was not functioning at all. No lights no attempt to switch into AWD, 4 hi, or 4 lo. Would not like to be out in snow and find out that 4WD does not work on a rear-wheel drive car. Could cause an accident.

- Roanoke, VA, USA

GM T-body 4 wheel drive vehicles 2002 > loss of control during 4-wheel drive conditions. Transfer case shifting in and out with out warning, causing a slide and spin out condition. Have been in touch with GM and was tolds condition is normal. They blame the driver is driving too fast for conditions. Other vehicles have not lost control under the same conditions and speed.

- Fremont , MI, USA

1st problem (exact date unknown, winter 2003-2004): The "check 4WD" light came on. The dealership's service dept said GM had no repair for this problem and that it was common in Trailblazers, and they simply reset the fuse. Then (May 2004): Vehicle started making a growling noise. We took it in and the mechanics said that one of the bearings was bad, and they replaced the bearing and rebuilt the transfer case. A month later (June) we had the same problem. That time, all of the bearings and the oil pump were "scored." Nobody suggested a reason for this. The transfer case was rebuilt again. Now (6 weeks later) the front differential is leaking oil from at least two locations and is currently being rebuilt. I have been told by the service dept that the reason is likely that "either it was put together wrong at the factory or the seal was bad to start with." It seems to us that the entire 4WD capability of this vehicle is compromised. We live in the country where the roads don't get plowed with any regularity, and with winter coming, I am going to need the 4WD, but I'm afraid to use it. I already spun out once last winter because they told me not to drive the car in A4wd because it's bad for the car, so I was driving in 2wd when I unexpectedly lost traction and did a 360 and almost wound up in the ditch. Even without snow, I am not confident that this car will get me "from here to there" without a problem.

- Eau Claire, WI, USA

While driving consumer noticed that service four wheel drive indicator was flashing. Technician upgraded computer, and replaced transfer case.

- Sturgeon Bay, WI, USA

While driving, the consumer noticed that the four wheel drive indicator light flashed intermittently. The dealership serviced the vehicle, upgraded the computer system and replaced the transfer case.

- Sturgeon Bay, WI, USA

While driving consumer noticed that 4-wheel drive indicator light flashed intermittently. Dealership serviced vehicle, but could not duplicate the problem.

- Hodgenville, KY, USA

The accelerator pedal position sensor failed causing loss of power to the vehicle. The vehicle would only accelerate to 10mph and almost caused an accident. I also had/have numerous other problems with the vehicle.

- Portage, MI, USA

When disengaging the 4-wheel drive vehicle jumped forward hitting a parked vehicle.

- Maywood, NJ, USA

'03 Trailblazer has been back to the dealership 7 times for the same problem, the 4 wheel drive engages by itself at 55 to 60mph, the truck jerks and it flashes from 4 wheel to 2 wheel drive, they have reset codes, changed switches and it still is doing the same thing. It has this problem at all speeds, it just is very noticable at higher speeds, the way the truck jerks..I have filed with the BBB.

- Leland, NC, USA

My 11-month old 2003 Chevrolet Trailblazer has had multiple quality problems, twice affecting my safety. Most of the problems have been electrical in nature. The 4WD has become inoperable numerous times, once while driving in snow. In another incident during a severe thunderstorm at night the air conditioner (A/C) failed and I was unable to defrost my windshield in order to see. After one dealer failed to diagnose the 4WD problem, another dealer replaced my ignition switch because the technician said I had no power at all going to the "rear grid." I continue to have intermittent electrical problems, including near stalling at a traffic light, and ongoing 4WD failures. The car also has very jerky motion when in 4WD reverse, of course, when the 4WD is working at all. The dealer told me that was normal and now I see there is a service bulletin on the problem.

- Arnold, MD, USA

While driving, unexpectedly the 4-wheel drive light went off. When this occurred, it rendered the 4 wheel drive inoperative. This was caused by a failure in the tcm module. The dealership reprogrammed the tcm module, but the problem recurred. Several tsb bulletins were issued on this problem.

- Springfield, NJ, USA

Upon starting the vehicle, the service 4-wd indicator light in the console area lights up, and the setting selector light does not work. The selection switch does not light up. The vehicle is new and has only 750 miles. When the dealer was contacted, I was told the service department could not look at the problem for 10 days. Additionally, I was informed that while the vehicle is probably safe to drive until they (the dealer) could assess the problem, the four wheel drive would not be working! having just been in an accident in another vehicle that was totaled, it does not give me a sense of security driving a vehicle that is not operating properly.

- Stamford, CT, USA

Problem with 4X4 shift indicator not registering transfer case position.

- Mansfield, MA, USA

Transmission locks up, 4 wd lights move on its own, this has happened 4 times since I have owned this car, I requested that I do not want this car back, but they insist they fixed the problem, now with my children 2 and 16 years in the car the 4WD light was malfunctioning and the car locked up and we skid down the street. I donot want this car back, I feel it will kill one or all of us with this lock up of transmission and the car won't move thank god it has not happened on the freway I feel we would be dead. The cars a lemo0N and I am not waiting for it to harm my familly.

- South San Francisco, CA, USA

Cosumer states the vehicle four wheel drive would not engage while driving. Vehicle taken to the dealer for repirs and the problem would reoccur. Feel free to provide any further information.

- Johnson City, TN, USA