03 Grand Prix GTP - Slight Grunting Sound When First Moving

I recently purchased a 2003 Grand Prix GTP from a dealer in my city. I took it for a test drive and everything seemed fine. However, now that I've had it for a few days, I've started to notice something. After the car has been sitting for awhile, it will let out a short (fraction of a second), relatively quiet grunt/rubbing sound shortly after moving after being put in gear. If I first drive in reverse, it often does this after backing up approximately 20 feet, and sometimes right when I first start moving forward after shifting to drive following reverse. If I immediately start moving forward in drive rather than reverse to start with, it generally takes about 20 feet again before it makes the grunting sound. After it does it this first time, I don't hear it again until the car has sat for a few hours and I drive it again.

My first thought was that it had something to do with the brakes. I contacted the dealer, and they said that the rotors had been turned and new pads were put on, and that the car had then sat on the lot for a month. He said that this sometimes happens when rust forms on the rotors, and it will take some time for it all to wear off. Does this sound like something that could cause the grunt or am I being fed a load of BS? I'm just hoping that I didn't buy this car (which has no warranty) with a transmission already on its way out. I haven't felt/ heard any other problems with the transmission, but I'd like to find out sooner rather than later. I realize that I didn't give an overly detailed description of the problem, but hopefully it will be a start.

Any thoughts? Help would be greatly appreciated.

-407

Reply to
Aaron407
Loading thread data ...

Nobody has encountered this problem before? Or maybe I'm being a little hasty, I guess it's only been posted for 13 hours :-)

Reply to
Aaron407

Have you tried lubricating the sway bar? Spray White Lithium grease on the rubber mounts and see if that helps.

Reply to
edsinmt

After doing a little more experimenting, I'm pretty sure it has something to do with the brake system. I drove for a short distance (~30') with my foot slightly applying the brake while still accelerating with the other. When it normally would have grunted, I felt the brakes shudder under my foot and there was a slight grinding sound, almost as if the ABS temporarily kicked in. Could it be possible that the ABS control module is quickly applying the brake, then letting it off? Or would it still be possible that rust on the rotors could cause this? I can still see a small amount of rust on the front rotors, and much more on the back ones.

Reply to
Aaron407

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.