Pontiac G6 Forum banner

1 - 17 of 17 Posts

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #1 ·
I have a 08 Pontiac G6 GXP with a front end vibration issue. Replaced all 4 wheel hub assemblies, both front struts assemblies, entire cv axle including the intermediate shaft. Both front brake calipers, rotors, brakes, sway bar bushings, sway bar links. All brand new good year tires balanced and alignment. Motor mount was replaced as well and I am still getting a vibration coming from the car when accelerating and sometimes a bumpy ride at highway speeds on a smooth brand new road. Only 77,350 miles on the car and I replaced the Transmission fluid, spark plugs. Any ideas why this is happening or is there a fix. I think it could be the transmission gear differential part causing the vibration. Any ideas anyone.
 

·
Registered
Joined
·
296 Posts
Take a close look at the brake calipers/rotors. I've had this show up a couple of times on my 08 gt. Caliper was binding up and man what a shake.
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #3 ·
Thought that was it but replaced the entire both front brake caliper, brakes, and rotors for the front and still vibration when accelerating. I think its the Torque system in the transmission or the Gearbox with the differential in the transmission. All other possible parts are brand new. Struts assembly, all 4 Wheel hub assemblies, sway bar links, sway bar bushing, motor mount, new tires, balanced and alignment, Changed the entire CV axle including the Intermediate axle bar. Car drives straight down the highway. Running out of parts to change since the entire front end is new. Only thing left to change is the lower control arms which are in good shape or the entire knuckle or replace the entire engine and transmission. Car only has 77,350 miles. Very frustrating trying to fix this issue. Any other thoughts anyone. Thanks.
 

·
Registered
Joined
·
296 Posts
Last thought before you go to more extreme measures...
About 2 years ago mine developed a real bad shake and found a bad inner CV joint on drivers side. On removal it was ALSO FOUND that the steering knuckle had cracked at the ball joint stud hole from somebody prior overtightening the pinch bolt. So I'm saying to really check over the steering knuckles.
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #5 ·
Last thought before you go to more extreme measures...
About 2 years ago mine developed a real bad shake and found a bad inner CV joint on drivers side. On removal it was ALSO FOUND that the steering knuckle had cracked at the ball joint stud hole from somebody prior overtightening the pinch bolt. So I'm saying to really check over the steering knuckles.
I wish it was that but I also replaced that part as well as I was getting a clunk noise when I turned the wheel and accelerated. So that noise went away but still have the vibration.
 

·
Registered
Joined
·
296 Posts
Okay, so you say you've gone thru everything and commented on other threads here of the problem. What model of Goodyear(badyear) tires did you have put on? LS11 are CRAP. I suggest you take it back and have all 4 tires spun for balance AND tire "squirm" (lack of a better term) as it spins. I've seen this many times in my years as an auto tech, and YES ON NEW TIRES.. It is a "luck of the draw" when getting new tires, and an HONEST installer will take note of such when doing the mount/balance. At least I did when I did that kind of work.
My well used 180K mile sedan always had some noise/vibration that drove me NUTS till I finally broke down and bought 4 new tires and watched them spin balance them. Mind you, these are the FIRST set of NEW tires that I have put on this car. The 2 sets of wheels that came with it did'nt look bad for abnormal wear but road noise and slight vibration was always there. With these NEW tires, and for the record they are VIVA 111 model it now rides smooth as silk. Such a low profile series amplifies any small abnormality in the tire and transmits it to the car.
GOOD LUCK!
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #7 ·
Thanks for the post but the car was doing the exact same thing with the old tires so I don’t thinks it’s that but I have the Goodyear assurance comfort tires. The vibration is felt on the floor board when accelerating. Engine moves when you accelerate as does any car do something touches the frame to cause the vibration. I am thinking sub frame bushings, so either way I have an appointment with the dealer on Wednesday.
 

·
Registered
Joined
·
296 Posts
Well you can "don't think" all you want...It's your car and your choice.
If mine my suggestion STANDS. Even a "road force" balance will NOT take away a tire imperfection. Mine did the floor vibration and what was attributed to "road noise" before getting new tires.
 

·
Registered
Joined
·
674 Posts
I have to say that from the description and what you have replaced I was also thinking tires / balance. My experience with this type of vibration is that it only occurs across a certain speed range. Faster or slower and it will diminish. If it were mine I would consider having the tires balanced at a different shop. Based on some shared experience locally we felt that a particular store had a faulty or uncalibrated balance machine. Having them balanced elsewhere fixed our problem. Hope the dealer can help and just a thought in case you have not considered this. Good luck with the fix.
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #10 ·
I have to say that from the description and what you have replaced I was also thinking tires / balance. My experience with this type of vibration is that it only occurs across a certain speed range. Faster or slower and it will diminish. If it were mine I would consider having the tires balanced at a different shop. Based on some shared experience locally we felt that a particular store had a faulty or uncalibrated balance machine. Having them balanced elsewhere fixed our problem. Hope the dealer can help and just a thought in case you have not considered this. Good luck with the fix.
I hope it’s that but before I replaced the old tires car was doing the same exact thing. It’s only when I accelerate that I get the vibration through the floor board and it doesn’t happen all the time, about half the time. If I coast, car drives smooth. So very confusing and frustrating after all the work I put into this car.
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #11 ·
I hope it’s that but before I replaced the old tires car was doing the same exact thing. It’s only when I accelerate that I get the vibration through the floor board and it doesn’t happen all the time, about half the time. If I coast, car drives smooth. So very confusing and frustrating after all the work I put into this car.
Forgot to mention the 18” factory wheels have abs plastic over the alloy rim. Don’t know if this is causing the vibration since it looks like it’s glued on permanently.
 

·
Registered
Joined
·
296 Posts
Did not post my remarks as a this is your fix. It is something to have CHECKED. Sometimes rechecking work done WILL find a fault with new items done.
 

·
Registered
Joined
·
296 Posts
Spent my morning doing my mowing and was still thinking about this mysterious problem....
You reported doing about all that could be done to the FRONT END.
Front vibrations would also be highly noted thru the steering wheel and a bit thru the floorboards. I don't recall you saying thru the steering wheel, MAYBE besides rechecking tires you ought to look into rear end parts. Rear end problems will definitely transmit thru the floor boards.
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #14 ·
Ok I will keep that in mind I did replace both rear hub assemblies as well. Thanks nothing thru streering wheel though. only on acceleration.
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #15 ·
Ok I have the results from the dealership. All the suspension parts and brake parts and axle replacement I did to the car is perfect. No issues there. Their seasoned mechanic took my car for a test drive and noticed the vibration occasionally when accelerating. Nothing major he informed me but the muffler system is causing the vibration. Car is 13 years old. There is no fix unless I want to replace the muffler system. Around 3ft of the down pipe was replaced before I purchased the vehicle already. So stuck with the slight vibration for now until the muffler system fails then I would get it replaced but not at the dealership, too expensive. So there’s my mystery people. I appreciate everyone’s feedback. Either way I still love my Pontiac G6 GXP.
 

·
Registered
Joined
·
296 Posts
Well that certainly can cause a "Vibe" in the floorboards! Would have been nice to know of exhaust "fix" that had been done. If it continues to bother you...maybe a good muffler shop could make an "adjustment" to the system to gain adequate clearance and get rid of the "Vibe"!
Thanks for posting back with the "results"!
 

·
Registered
2008 Pontiac G6 GXP, 3.6L V6 sedan
Joined
·
23 Posts
Discussion Starter · #17 ·
Ok everyone who replied and followed this issue. The muffler resonator was removed with a straight pipe. This caused the excess vibration coming from the car. Apparently previous owner went the cheap way to fix a rusted part from the muffler system. The resonator is there for a reason. So people be aware our cars are getting older do not substitute straight pipe for the resonator.
 
1 - 17 of 17 Posts
Top