Automatic Transmission problems of the 2003 GMC Sierra

The transmission clunks when shifting from 2nd - 3 rd and at times the engine will rev and finally it will take off, this has caused an issue when going through an intersection. The dealership attempted four repairs and it is not fixed. The issue started when the vehicle had 6k miles on it and it is getting worse. The speedometer is sporadic in that it will show speed reduction/increase in segments - as if it were sticking. The erroneous speed indication causes an issue when going too slow or too fast in traffic.

Transmission: been fixed 3 times and finally replaced a/c: repaired once front end-steering: repaired 3 times and still not fixed.

I drive a 2003 GMC Sierra and there is a transmission problem it makes the driving very dangerous especially at highway. Speed. The vehicle cannot stay strait it either pulls to the left or to the right. The feel of the vehicle isn't right like if its dog tracking. There are clonking and ticking sounds coming from the transmission just from shifting from drive to reverse,reverse to drive. . . Park. While driving when engaging the passing gear sometimes you hear that clonking sound like if there was a slack in the transmission. I had this vehicle since July 2004 and since then I've been to the dealership a number of times everytime they said that everything was ok and showed me paperwork stating from gm canada that clonking, ticking etc. Etc. Were normal operation of the transmission. It cant be cause I had a 2001 GMC truck which I traded for, that drove like a truck this one I have now drives like a tank. Every hole or crack in the road I can feel when I hit a small hole or a dip in the pave the vehicle wants to dog track most of the time the truck pulls to the left, when it does there is a slight vibration you can feel from the accelerator or the brake. This vehicle I find is a accident waiting to happen. Its a big vehicle and to swerve side to side scares other vehicles on the highway, which puts everybody at risk everytime I'm on the road. From all these complaints I did to gm still today they tell me and show me paperwork from gm tech line. Stating that everything is normal and no work from there part should be done on this truck. It's like if gm has people working on these statements just to cover themselves from having to repair or change parts in order to save money in which I wouldn't dought. If you can help me please. Let me know cause this is a very serious matter which I would like to fix before I get into an accident. I believe there is a controversy into all of this.

I purchased my 2003 GMC Sierra z71 in Aug. 2003. In December 2003, while pulling a travel trailor, the service 4-wd light came on and the truck felt as if it had been shifted into neutral. I managed to get the truck to the side of the road and read the owners manual concerning the light. I turned the truck off as the book said and then restarted. The light stayed on, but the truck did go in gear. Since this time, when I pull the trailor for a long period of time, the truck will again feel as if it is in neutral. I have to put the truck into 2nd or 1st gear to get the transmission to engage. The 4wd light comes on with or without the trailor hooked up and has been checked several times by the dealer. They have replaced the switch but this has not corrected the problem. The transmission shifts so hard it feels as if the back end of the truck will fall out. I was told this is normal operation. Something needs to be done to correct this problem as this is a huge safety issue. No one can feel comfortable driving down a road and never knowing if you will be hit from behind due to this truck stalling for no reason.

2003 GMC Sierra slt z71 extended cab, 13000 miles. Transmission shifts slowly and slips between 1st and 2nd. Drivetrain very very noisy between up and down shifts. Knocking in steering wheel.

2003 GMC Sierra, 7000 miles automatic transmission is jerky. Very poor performance. Service department refuses to acknowledge the problem. I know for a fact this is fairly widespread. What can the dealer do about it?.

While driving at any speed vehicle has a problem shifting into a gear. When the gear is changing there is a hard thump/a brief hesitation before the gear actually goes in to the proper position. Vehicle had been to the repair shop five times for this same problem, but problem still persists. Dealer and manufacturer have been notified of the problem.

While driving the fourth gear of the automatic transmission jumped. The dealer inspected the vehicle but could not duplicate or correct the problem.

When vehicle was stopped on an incline with gear placed in park before engaging parking brake the transmission locked in park. In order to unlock it the consumer had to have the tow truck pull the vehicle in order to unlock it. The manufacturer advised that this was normal operation. Truck is a 2003 GMC 1/2ton 4-wheel drive pickup.