Four problems related to differential unit have been reported for the 2003 GMC Sierra. The most recently reported issues are listed below.
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?.
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. When discussing this problem with the dealers service manger and now finally with the general manger, they still say this is normal and has been for all 2000 through 2004 GMC Sierra's. That's interesting, because I owned two 2000 GMC trucks in the past and neither one of them experienced these problems.
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.
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 selected a truck bigger than what I needed at the current time, thinking that if I replaced my travel trailer in the future, I would not have to trade trucks also.