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 2003 GMC Sierra owners, lightly cleaned up (personal details are redacted by NHTSA).
On May 31st, the rear end differential assembly exploded sending the pinon thru the housing and the rear axle caught on fire. The truck was in the shop (perry cheverolet, inc., columbia, mo)until 6-9-03. When I arrived in bozeman, mt on 7-2-03 I was having problems with the wiring. There was a fire when I plugged the rv electrical plug into the truck's trailer plug. There was also a blown rear tail light bulb. In bozman, they replaced the complete wiring harness, the tow receptacle and 2 fuse kits. It was the opinion of the shop in bozeman (j.c.billion, GMC) that the wiring damage was part of the original fire and differential assembly damage. Although GMC paid for my out of pocket expenses and for the waranty work, I am left to wonder what will happen next and just how safe am I going to be in this truck? …
I was parked on a sloped driveway (about 10 - 15 degrees). I started the engine, stepped on the brake pedal and took the car out of park into drive. Brake pedal was normal. I started to roll forward and when I pushed the brake pedal the car did not slow. I slammed the brake pedal and it went all the way to the floor. At this point I went off the end of the driveway onto a 45 degree downward sloped lawn; then into a wooded area at the top of a ravine. I slammed into a tree. The car was judged a total loss by my insurance company. I did not get a brake warning light. The airbags did not deploy. The car was serviced at a union park GMC (wilmington, de) two days prior. Including brake inspection. Cause of brake failure was determined to be ruptured brake line. Both front and rear brakes were failed.
Truck was entering major highway,traffic begins too slow due to rush hour ,seeing this occur I stepped on brakes expecting to slow down ,until I realized pedal had gone all the way to floor,then I let up an pushed to floor again-no brakes no room to go left or right impact was unavoidable,impacted car twice which pushed that car into another this truck was serviced by GM dealer for transmission cooling line and engine cooling lines Monday Tuesday and Wednesday, no mention of brake lines issue, accident occurred on Friday. Also had contacted GM about original work re: possible warranty. Updated 07/25/12 the consumer has since traded the vehicle. Updated 07/31/12
I own a 2003 GMC Sierra 1500 z71 off road truck. I've had it in the shop four times now due to the same problem. The problem consists of excessive play/backlash in the rearend/differential according to the dealer. This excessive play/backlash is causing the truck to jerk after shifting from first to second and second to third gears. The dealer and manufacturer say this is normal according to GM specs. At one point, while sitting at a traffic light, I proceeded to accelerate after the light turned green and the truck didn't go anywhere, but after a few seconds the truck slammed into gear and spun the rear tires. This problem seems to have been corrected after replacing the transmission control solenoid for now, but the constant jerking of the rearend/differential seems to be worsening. …
I own a 2003 GMC seirra 4x4 sle (ext) cab and the transmission is very jerky between first and second gear and between second and third gear also , but at times there is a cluck noise between second and third gear. Which sounds like a universal joint that is bad.first time I took it to the dealer they said they couldn't reproduce the problem. Second time they change the pressure control solenoid in thethe valve body, filter, and fluid in transmission. It worked great for @ two weeks and now it's back. There is a problem here . Two friends at work have the same problems with there 2003 GMC's and Chevy's trucks.
I have a 2003 GMC Sierra 1500. At 1300 miles, I lost a fitting that connects the transmission line to the radiator for the tranny cooler and the transmission was destroyed. A rebuilt transmission was put in my pickup. I now have 32000 miles on it and the transmission seems to "double" shift between 2nd and 3rd gear. I've had my truck in the shop 5 times to diagnose this problem. The dealership cannot reproduce/find the issue. The pressure control solenoid was replaced about 4 days ago. The transmission is still acting up.
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.
I own a 2003 cmg 1500 4x4 when I had 300 miles on vehichle I noticed a vibration in the drivetrain. I took to dealer, they adjusted tire air pressure. 2nd time in they changed bearing in front differential, 3rd time in they changed front differential carrier, this got rid of vibration, I still have a concern that the carrier come as a shell so it still has original ring and pinion. Don't no if this will create a problem later or not but gear patern must have changed.
I have a 2003 GMC Sierra pickup.my problem is the transmission does not work properly.I had 150 miles on the vehicle when the trans blew,now a clunkling noise every time the vehicle shifts.GM calls this a downshift clunk noise and has issued a TSB requesting dealers not to attempt repair.this is a loud clunk which slams into the differential.I have contacted GM to no avail etc runaround. Is there any place to get help for me and possibly many others?
Tl contact owns a 2003 GMC Sierra. While the contact was examining his vehicle he noticed that there was oil dripping from the transfer case under the vehicle. The vehicle was taken to the dealer where the contact was informed that a cover should be put on the transfer case to stop the leaking. The vehicle was serviced by the dealer and there were no prior warnings. The current and failure mileages were 76000.
Transmission complaints in other Sierra years
Frequently asked questions
How common are transmission problems on the 2003 GMC Sierra?
NHTSA has 29 complaints about the transmission & drivetrain of the 2003 GMC Sierra, 14% of the model year's 206 complaints. The component named most often is automatic transmission (15 mentions).
Is there a recall for 2003 GMC Sierra transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2003 GMC Sierra, though it has 6 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 2003 GMC Sierra transmission problems start?
Half of the complaints with a recorded mileage happened before about 4,000 miles, and 71% before 25,000 miles.
Is it dangerous?
Owners linked 2 crashes, 1 fire and 2 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.