2003 GMC Sonoma SLS Extended Cab....REAR-AXLE PROBLEMS...NEED HELP!!!?

Guy with Truck Problems · #1 09-30-2009, 11:02 AM

Ok...here is my problem. I just bought a 2003 GMC Sonoma SLS Extended Cab from a certified dealer at the beginning of August. There was zero problems with this truck, and it ran beautifully. Well, lately, I have noticed a popping/thumping noise when I accelerate and decelerate. I didn't think too much of it at the time, and decided to go get the entire undercarriage looked at. The tires were fine, the brakes were checked, and even the drive-train was oiled again. But, here in the past 2 weeks, the popping/thumping has gotten worse, and it gets worse as I accelerate, and it shakes the entire vehicle and the noise can be heard pretty clearly from outside of the truck as well. I have been told that it could possibly be the U-Joints, and then again I have been told that it could possibly be that the oil in the rear-axle needs to be replaced, and I have also been told that the entire rear-axle may need to be replaced/re-built. Can anybody tell me what is going on here?

And, another question. I have been notified that GM puts out a 100K drive-train warranty on all of their models. If that is true, does this truck have a GM warranty at all? It only has 72K miles on it right now. Can anybody tell me about this as well?

Thanks!

epiphaknee · #2 12-09-2009, 04:29 PM

The first step is to contact your GM dealer and find out what the warranty is on the drivetrain. If it is 5 years or 100,000 miles then you might be out of luck but they can tell you in a few minutes.

Yes, this sounds like the U-Joints or the slip yoke. The yoke receives the front of the driveshaft but can loosen up over time. However, a loose yoke does thump and clunk and pop, as you mentioned.

I wouldn't think the fluid in the rear differential would cause this problem unless there is no longer any fluid in the rear differential. Yes, a bad differential could cause a look of road noise and you could hear this both inside and outside the car. Just remove the filler plug on the differential and stick your little finger in there to determine if you have enough fluid in the rear diff.