Thread: Mysterious Noise - 02 GTP Coupe

Originally Posted by ScottyDoggs

if its a bad axle the vibration will go away when your off the gas and coasting. if its still there have the alignment checked and the tires balance. try rotating the tires front to back, see if it goes away.

This might be my problem on my new Grand Prix. I've noticed over 40mph or so getting on gas there's a vibration that can be felt through the pedals and the steering wheel, but not bad enough to shake like that video above. CV Axle?

Agreed. Out of town at a conference but sweetie agreed to take it in to the local tire place for an alignment and re-balance. Will see if it did the trick. Bear in mind these are brand new Goodyear tires.

Funny thing about the noise...once you got to 35 or so, you could hear this scraping crunching grinding noise, and it was loudest with the passenger window down. Didn't get louder if you went faster, didn't go away until you got down below 20 or so. Th bearing had so much play I figured it was the problem, but it wasn't making the noise, it was the axle.

I only had a verrrry slight vibration before I did anything....the vibration didn't get bad until I changed the hub, axle and brakes. If the tire balance and alignment doesn't fix it, next will be hub and axle on the drivers side. Stay tuned.

Yeah yeah....well, the wheel balance and alignment smoothed it right out at all speeds. Not sure what happened outside of maybe losing a wheel weight...

Anyway....cruising along enjoying the smooth ride...and.....wait for it.....the noise is back and louder than ever. Apparently whatever is complaining needs time to warm up before making noise, and I guess I didn't run it long enough on my last test drive after putting the axle in.

So with both windows down, it seems a lot louder on the passenger side still. Next suspect is the RR hub bearing and will do rear brakes as well. Confirmed that symptoms appear about 35-40 mph, no change while braking, not engine speed related. Stay tuned.

Installed a set of rear brakes yesterday along with a RR hub bearing. In the process discovered the e-brake assembly on the RR was corroded and binding, and wasn't releasing properly, so added some lube on the activator assembly and seems to work OK now. Put it all back together and by the time I got to Costco is was screeching worse than ever. So it's definitely brake related, and am leaning towards the caliper not fully releasing. I greased the caliper pins when I did the brakes and all seemed to work OK, so it's possible the brake hose is bad.

Fortunately moving in a few weeks to a place with a garage so will have time to do some diagnostics on this instead of throwing more parts at it. Living in this small apt since moving back to LI and borrowing my buddy's driveway to work in, so haven't been able to spend any real time with this beyond what it takes to change a few parts.

Any additional ideas welcome, or maybe a smartass gif or two....