I picked up my GXP with M6 January 9th. I love driving it but noticed a vibration from day one. It only starts above 45 mph. The dealer service department said it was the tires. Since it sat on the boat and in the shipping lot for so long it could have flat spots on the tires. This did not sound right to me. They balanced the tires and this did not help. went back 2 more times, same thing. Rebalance tires and no help. I kept telling them it has to be in the driveline because it did not matter what gear the car was in and you could feel it coming through the seat. I had a mustang that droped a driveshaft balancing weight and it felt similar. Finally a good mechanic at the dealership found a GM service bulletin dated October 2 2008.

It is titled "Drive line Boom Noise And/ Or Vibration". It is for "2008 - 2009 Pontiac G8". He tried realigning the center support bearing assembly. And tried indexing the prop shaft to the differential yoke. None of this worked. So now the have to order me a new driveshaft assembly. They cant even get a part number from GM. They dont know when the can get the part number or the parts. I assume its coming from Australia.

Does any one know if the automatic transmission G8 GT has the same driveshaft as the M6 in the GXP? probably not because of transmission lenghth.

Has anyone else heard of or had this problem with their car?

Thanks.

I have the same issue, I was thinking it was coming from the AFM, however, recently started driving it in M-mode, and I still have the same issue. I guess I will be taking in as well

Thanks for the info

Well since this car/chassis has been out in Australia for over two years now so hopefully the feedback/fixes will make it this way over the pond.

Good luck getting it fixed!

It's definitely a bummer to have a problem with the car. But, what I like about the story is that there appears to be a "path forward". At least there was a service bulletin and at least someone found the service bulletin. All of this is better than having someone stare you in the face as if you have some kind of mental problem.

Don't you???? HaHa

I've experiened the same vibration with my GXP; It's most prevalent under moderate load, usually in 2nd gear. Im taking it to the dealer this weekend

Bummer BR6! WhiteDeathLSX is yours a M6 also? Valkim I hope they don't try to give you Sh@* about the change in wheels (they're HOT by the way) causing the problem. Some dealers I've dealt with in the past have tried that crap to get out of covering known problems. Good Luck on the fixes and as always Keep us all posted.

I had this problem with a early production 95 z28, I couldnt drive it past 70 without it feeling like it was going to break apart.

They had to replace two driveshafts before the problem went away. Perhaps its the same supplier?

Best of luck...

Here is the full bulletin. It is under Bulletins, Campaigns or Preliminary Information from SI2000. Hope this helps and gets the info out.

#PIC4989: Drive Line Boom Noise And/Or Vibration - (Oct 2, 2008)

Subject: Drive Line Boom Noise and/or Vibration

Models: 2008-2009 Pontiac G8
--------------------------------------------------------------------------------
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
There may be a either a boom noise or vibration and in some cases both a noise & vibration detected in a very few 2008 & 2009 G8's. This condition may be detected by customers at speeds of 55-65 MPH on either 08 or 09 G8's. The noise could be described as a low frequency boom or moan noise (not a whine) coming through the body. The vibration is generally felt in the seat or the floor pan. The condition could be caused by either a misaligned center support bearing assembly or the prop shaft mounting to the differential yoke.

Recommendation/Instructions:
The prop shaft center support mount is slotted left to right and can be adjusted by loosening the bolts which are accessible through holes in the metal shield between the prop shaft & the floor sheet metal. After loosening the center support bolts you can use a pry bar between the prop shaft & floor to adjust the center support. If the alignment isn't correct the prop shaft will usually "snap over" into proper location with very little input.

If the condition is both noise & vibration felt through the floor, re-indexing the prop shaft to the differential yoke may have to be performed:

Mark the relative alignment of the propshaft, rubber coupling, and differential in the original position.
Number the nut and bolt pairs and their hole in the rubber coupling which join the rubber coupling to the differential (silver) and the nut and bolts which join the propshaft to the rubber coupling (black).
Remove rubber coupling from differential and propshaft, ensure the nut and bolt pairs are kept together.
Re-assemble indexing the rubber coupling and silver bolts clockwise (relative to differential), and the propshaft and black bolts counter clockwise (relative to differential).
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Most major cities have driveline specialty companies where you could take the entire prop shaft assembly and they will spin balance it. Certainly for a few bucks your dealer ought to be interested in this approach over making you wait for a brand new shaft.

There is even a chance that even if the sections of the shafts are designed to only go together in one indexed alignment that the actual indexing is off. I had this with a high speed (2000 rpm) wobble shaft where two of the 10 splines were supposed to be welded at the tip and the female half was made with one wide slot to accept this double spline. Took forever to discover that the weld was not there and that the shaft was off by only one spline.

I'm failing to understand how the service bulletin addresses an out of balance drive assembly.

I'm failing to understand how the service bulletin addresses an out of balance drive assembly.

It doesn't. It addresses mis-aligned center support bearing. But if the outlined procedure fails to correct then an out of balance issue may exist. $50-$100 after removal of driveline from vehicle can determine any balance issues of the shaft itself.

If I have this problem then I'll do the aligning of the support bearing myself. If it doesn't help then I'll take it to the dealer.

I'm right there with you 99 - hell - the bulletin tells you EXACTLY how to do it. Anyone with a basic set of tools could do it themselves.

I'm right there with you 99 - hell - the bulletin tells you EXACTLY how to do it. Anyone with a basic set of tools could do it themselves.
And a 2-post lift.

And a 2-post lift.

I have access to two of them. :)

Not arguing at all. Eagerly waiting to be corrected. But, why do you need a two post lift?

I picked up my GXP with M6 January 9th. I love driving it but noticed a vibration from day one. It only starts above 45 mph. The dealer service department said it was the tires. Since it sat on the boat and in the shipping lot for so long it could have flat spots on the tires. This did not sound right to me. They balanced the tires and this did not help. went back 2 more times, same thing. Rebalance tires and no help. I kept telling them it has to be in the driveline because it did not matter what gear the car was in and you could feel it coming through the seat. I had a mustang that droped a driveshaft balancing weight and it felt similar. Finally a good mechanic at the dealership found a GM service bulletin dated October 2 2008.

It is titled "Drive line Boom Noise And/ Or Vibration". It is for "2008 - 2009 Pontiac G8". He tried realigning the center support bearing assembly. And tried indexing the prop shaft to the differential yoke. None of this worked. So now the have to order me a new driveshaft assembly. They cant even get a part number from GM. They dont know when the can get the part number or the parts. I assume its coming from Australia.

Does any one know if the automatic transmission G8 GT has the same driveshaft as the M6 in the GXP? probably not because of transmission lenghth.

Has anyone else heard of or had this problem with their car?

Thanks.
I hears the same thing from a GM Tech regarding the support bearing, I believe thats the only TSB regarding this issue, now having said that I have owned many a new GM vehicle & anytime there was a vibration issue over 45mph, I scrapped the factory rubber went out & bought a really good set of rubber & presto, problem gone, was going to buy a GXP, but all of the problems I keep reading about the G-8, I have changed my mind.
Enormous amounts of serious problems, I'll buy something tried & true, good luck with your car.
sparky56

was going to buy a GXP, but all of the problems I keep reading about the G-8, I have changed my mind.
Enormous amounts of serious problems, sparky56

What kind of enormous problems have you read about? If sparky doesn't respond, has anyone else read about these problems?

What kind of enormous problems have you read about? If sparky doesn't respond, has anyone else read about these problems?

Besides this serious yet isolated vibration issue (which isn't stranding owners) or the flacking steering wheel paint I'm not sure as well what old Sparky is talking about ?? :sneaky:

I have an update on my driveline vibration. The dealer ordered a new driveshaft. GM had to pull one off of the assembly line in Australia. No one had one in the states. I figured that would be the case. The dealer installed the driveshaft. It made a huge difference.
I love driving this car. I have to be careful driving on the highway. When I look down at the speedo I cant belive it. It rides smooth and fast. It feels similar to my 2005 Corvette on the highway. I will attach some pics. of the driveshaft.

I'm glad it made a difference. I can't wait to get my GXP!!!!

I haven't had time to take mine to the dealer. The vibration continues (700 miles on the odometer)... I'll be taking it this weekend and hopefully it will go away :)

I don't think I have this issue yet, but what exactly does it feel like? Are you feeling a huge vibration?

I will try to get some pics up, bit pissed got the windows tinted and they failed! Got some bubble spots need to get that fixed. Probably need to go somehwere that is not having a "special" LOL

We have over 1000 miles and no vibration noted as of yet

I had the "boom" noise but no vibration that usually started right at 55 MPH but would end at 70 MPH and I only have 450 miles on the car. Until I read the TSB I actually thought it was normal. I just had the dealer perform the adjustment from bulletin #PIC4989 and now the noise is gone. The process only took about 30 minutes. It would be interesting to know what the build week and date was for people having this problem. Was Built in OCT 2008, Week 35.

I had the "boom" noise but no vibration that usually started right at 55 MPH but would end at 70 MPH and I only have 450 miles on the car. Until I read the TSB I actually thought it was normal. I just had the dealer perform the adjustment from bulletin #PIC4989 and now the noise is gone. The process only took about 30 minutes. It would be interesting to know what the build week and date was for people having this problem. Was Built in OCT 2008, Week 35.

How did you find out your build week?

I got my build week from the Pontiac Locator that I used to find the car before I bought it. It Lists the build week in the description. Here is an example.

http://i521.photobucket.com/albums/w338/DaMaine1/MY%20GXP/clip_image002.jpg

It says GM prod Week 35
Most 2009 1/2 started during that week.

I have a similar issue, just a slight vibration right around 100 kmh. I know its not the AFM as that is a different sound/vibration.

The dealer said they wont even look at it until 5000km

-Q

I picked up my GXP with M6 January 9th. I love driving it but noticed a vibration from day one. It only starts above 45 mph. The dealer service department said it was the tires. Since it sat on the boat and in the shipping lot for so long it could have flat spots on the tires. This did not sound right to me. They balanced the tires and this did not help. went back 2 more times, same thing. Rebalance tires and no help. I kept telling them it has to be in the driveline because it did not matter what gear the car was in and you could feel it coming through the seat. I had a mustang that droped a driveshaft balancing weight and it felt similar. Finally a good mechanic at the dealership found a GM service bulletin dated October 2 2008.

It is titled "Drive line Boom Noise And/ Or Vibration". It is for "2008 - 2009 Pontiac G8". He tried realigning the center support bearing assembly. And tried indexing the prop shaft to the differential yoke. None of this worked. So now the have to order me a new driveshaft assembly. They cant even get a part number from GM. They dont know when the can get the part number or the parts. I assume its coming from Australia.

Does any one know if the automatic transmission G8 GT has the same driveshaft as the M6 in the GXP? probably not because of transmission lenghth.

Has anyone else heard of or had this problem with their car?

Thanks.

Is there a TSB for this or some number my dealer could look up for this?

Yup Its TSB # PIC4989 and I would go to a different dealer if I were you. For them to not even check it is BS IMO. Good luck.

#PIC4989: Drive Line Boom Noise And/Or Vibration - (Oct 2, 2008)

Subject: Drive Line Boom Noise and/or Vibration

Models: 2008-2009 Pontiac G8
--------------------------------------------------------------------------------
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
There may be a either a boom noise or vibration and in some cases both a noise & vibration detected in a very few 2008 & 2009 G8's. This condition may be detected by customers at speeds of 55-65 MPH on either 08 or 09 G8's. The noise could be described as a low frequency boom or moan noise (not a whine) coming through the body. The vibration is generally felt in the seat or the floor pan. The condition could be caused by either a misaligned center support bearing assembly or the prop shaft mounting to the differential yoke.

Recommendation/Instructions:
The prop shaft center support mount is slotted left to right and can be adjusted by loosening the bolts which are accessible through holes in the metal shield between the prop shaft & the floor sheet metal. After loosening the center support bolts you can use a pry bar between the prop shaft & floor to adjust the center support. If the alignment isn't correct the prop shaft will usually "snap over" into proper location with very little input.

If the condition is both noise & vibration felt through the floor, re-indexing the prop shaft to the differential yoke may have to be performed:

Mark the relative alignment of the propshaft, rubber coupling, and differential in the original position.
Number the nut and bolt pairs and their hole in the rubber coupling which join the rubber coupling to the differential (silver) and the nut and bolts which join the propshaft to the rubber coupling (black).
Remove rubber coupling from differential and propshaft, ensure the nut and bolt pairs are kept together.
Re-assemble indexing the rubber coupling and silver bolts clockwise (relative to differential), and the propshaft and black bolts counter clockwise (relative to differential).
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Mine says Production week 35 too.

Well, Before you take delivery of your car take it for a spin and listen very carefully when you hit 55 MPH. If you have the problem you will here a very distinctive low tone groan that will disappear when you pass 65 MPH. The noise will be there even if your coasting and not giving any throttle. Like I said I did NOT have the vibration, and honestly other than there being a slightly different sound between 55 and 70, I assumed it was a normal characteristic of the car. But now after the realignment there is no noise at all at any speed.

Mine was a noise and a vibration. The noise and vibration started at 50 MPH. The noise was kind of like a buffeting sound you hear when the sunroof is open and the windows are up. The vibration was the more noticeable part. It only started above 50 MPH and the vibration could be felt in the seat. My vibration stayed at any speed above 50 MPH. It was worse between 50 and 70 MPH. Indexing the shaft did not work for my car. With the new shaft it rides great. The dealer first tried balancing the tires and I told them that was not it because I could feel it in the seat of the car. They made me wait and put at least 500 miles on the car to "let everything work itself in".

I forgot, I drove a G8 GT the dealer had on the lot back to back with my GXP for comparison. I also thoght part of it was just the nature of a GXP. If any one has this problem drive a GT and compare. They should be the same.

I know I have a vibration through the sterring wheel and it is not AFM. I can let go of the wheel and watch it vibrate back and forth. I am keeping track of each item I want the dealer to look at and they can tackle them at one time.

I know I have a vibration through the sterring wheel and it is not AFM. I can let go of the wheel and watch it vibrate back and forth. I am keeping track of each item I want the dealer to look at and they can tackle them at one time.

95% chance it's a wheel balance issue. You probably threw a wheel weight or hit a pothole a bit hard. I'd get that checked first.

:iagree:

I have a similar issue, just a slight vibration right around 100 kmh. I know its not the AFM as that is a different sound/vibration.

The dealer said they wont even look at it until 5000km

-Q


Bull****, be firm, but nice, and tell that lame ass dealer to do their job! It's a 30k car and waiting till 5000km to perform a known bulletin fix is utterly absurd!

95% chance it's a wheel balance issue. You probably threw a wheel weight or hit a pothole a bit hard. I'd get that checked first.


Yep. Wheel SHAKE is a balance issue with wheels/tires. The driveline "boom" is a weird harmonic vibration that can be felt through the floor and seats more, and can be HEARD as a low/deep vibration.

So the question is what to do when the dealership performs the TSB once but won't do it again as GM only wants them to attempt it once?

Okay all, mine is going in this week for driveshaft rebalancing.... a new part has been engineered (or designed) that reportedly could (or should) fix our driveline vibration issue (I'm going to presume it won't address steering wheel travel but hope springs eternal)...I'll report back later this week on results..helps when you have a great dealership who's committed to getting it right

I posted results under another thread. For those of you that are dealing with this issue get your dealer through GM to rebalance or replace your driveshaft and a coupling that is at issue (apparently a rubber part). I am driving a new car after the fix...had the driveline issue since day one..hard to believe it's the same car. I would have lived with the issue if I had to given that I love this car...but wow, what a difference when the car rides as it's supposed to.

I have not had the issue until within the last 100 miles or so (I'm at about 8,300). What's odd is I don't get the vibration from 55 and up. I get it in the 35-45 range when I'm holding steady (not accelerating) or on the decel. I'll probably have the dealer take a peek at the next oil change (Mine come fairly quickly. Usually every month and a half to 2 months. I get free oil changes from my dealer for life every 3250 miles. The catch is I don't get to choose which oil.)

I posted results under another thread. For those of you that are dealing with this issue get your dealer through GM to rebalance or replace your driveshaft and a coupling that is at issue (apparently a rubber part). I am driving a new car after the fix...had the driveline issue since day one..hard to believe it's the same car. I would have lived with the issue if I had to given that I love this car...but wow, what a difference when the car rides as it's supposed to.

I have had this same problem since I took ownership of my 09.5 G8 GT. I had the TSB done which did nothing to my car. The dealer service manager requested GM to replace the drive shaft but they refused and GM won't authorize the dealer I purchased the car from to do anymore work. I open a case with GM and they sent a GM rep to the dealership and he took a drive in my car with the dealer service manager and me. We hadn't gone a mile and he said there was nothing wrong with my car. He had his mind made up without even driving the car for 5 - 10 miles as I requested. What an incompetent idiot and a total waste of time for me. I now have 3,500 miles on the car and the vibration in the floor and low pitched noise continue at speeds starting at 55 miles or more. The car rides great at speeds below 55 miles. Where do you live and what dealer did the work? Do you have the name and telephone number of the service manager. I would like to call him and find out how he got the approval from GM to replace your drive shaft. Would like the service manager from the dealership I purchased my car from to call him.

I took my GXP in to the dealer for the vibration / drone and they said they it was normal. What a waste of time, the warranty is almost useless because my dealer never seems to want to fix anything under warranty even when theres a bulletin for the issue.

Is drive line vibration problem for all GXP's, I haven't noticed it yet, i got 5K miles on mine.I will pay more attention and see if i can feel it.
Will this drive line vibration cause any damage to transmission.

I have a vibration in my shifter - but it's only in 4th gear. Keep me posted on what you find out.

I have the darn issue as well. At first I thought it was some sort of DOD/AFM but after researching the GXP doesn't have that I know this is what it is.

Low speeds are fine up to 55-65mph and mine can be heard as you accelerate faster and faster. Almost like a deep humming you can feel in the body of the car. I had car aligned, and wheels balanced and it is not working. I have just 1100 miles on my car now.

I guess I wil get it looked at first thing monday and show them this bulliten.

Dougie

Low speeds are fine up to 55-65mph and mine can be heard as you accelerate faster and faster. Almost like a deep humming you can feel in the body of the car.



Add me to the list. I thought it was in my head, but I noticed it almost immediately when I took delivery. I can't feel it, but I can definitely hear it. Have about 4500 miles now. Hasn't changed in character at all.

NVH issues make me cringe thinking about going to the dealer to get addressed... Will have to make the trip though.

Well, i took the GXP to the Chevy dealer and the shop foreman looked up the bulletin and said they would give it a shot. He read the bulletin and pointed out that if it didn't take care of the vibration, as stated on the bottom of the bulletin that engineering is looking for fix for this concern. Hopefully this will take care of it. At least they are going to try, unlike Maxwell Pontiac cant fix anything.

Well, i took the GXP to the Chevy dealer and the shop foreman looked up the bulletin and said they would give it a shot. He read the bulletin and pointed out that if it didn't take care of the vibration, as stated on the bottom of the bulletin that engineering is looking for fix for this concern. Hopefully this will take care of it. At least they are going to try, unlike Maxwell Pontiac cant fix anything.

Chris did u buy the pontiac from Nyle maxwell , i also bought it from them (Victor) , i got my car shipped to california,mine is a black M6 and have no problems so far, I never felt the drive line vibration at all, Is it a problem for all gxp's.

Chris did u buy the pontiac from Nyle maxwell , i also bought it from them (Victor) , i got my car shipped to california,mine is a black M6 and have no problems so far, I never felt the drive line vibration at all, Is it a problem for all gxp's.

No, i didn't buy from Maxwell as they didn't have any left. I think it only affects some G8's. I could hear it more than feel it, it was just really annoying to the point of not wanting to drive the car.

Well, i took the GXP to the Chevy dealer and the shop foreman looked up the bulletin and said they would give it a shot. He read the bulletin and pointed out that if it didn't take care of the vibration, as stated on the bottom of the bulletin that engineering is looking for fix for this concern. Hopefully this will take care of it. At least they are going to try, unlike Maxwell Pontiac cant fix anything.
Hey Chrisx. I too am a GXP owner in G'town. I think you may be my neighbor from just down the rd. Mine is Silver. I had a SC'd 06 Goat and if I am correct you had a black goat too. If so, small world.
About the vibration... I had it somewhat with the stock crap, er tires. I put Michelins on and completely went away. I do still have a bit of a driveline droan (sound only-no vib) at 57-60 mph but its not bad and stereo must me off to hear it. I just do not cruise in that range.
Send me a note and we can get together, you can take a ride in my car and see how smooth the tires made it if you wish.
Hope this helps. Diesel (Rio Bravo).

Just got back from the dealer for the PIC4989 vibration TSB. Mixed bag. First off, the manager looked at me like i had 3 heads and couldn't find the PIC in the GM system which I looked up with my cell phone on Google and had to physically SHOW them. Guess I was a bit too presumptuous in not bring a printout of my own from home thinking a dealership might just have the info. Talk about holding their hand! They found it eventually in the bulletin but only after starting to diagnose the car. They acknowledged the booming (thank God) and confirmed it wasn't the AFM or alignment shimmy which was good because I was expecting the run-around with the typical "we couldn't find it" or "we thinks it's this" BS which is exactly why I got the first appointment of the day and STAYED in the waiting area in case I needed to do a ride-along with the tech. Reffering to the index from the factory as #1, I was told the first fix attempt, position #2, resulted in making the booming WORSE. Second try, position #3, made things better than the factory position (#1) but it is still not 100%. I'd say 40-50% better but not perfect and they were upfront about it before I even got to try the car, which is cool. The manager stated, per the TSB, there wasn't alot they could do other than put it into the best position of the 3 for now until "GM comes up with a solution" which I understood and actually kind of expected. My fear really was just that the service dept would make me work my butt off to get this fix going. I just wanted a temporary fix for now and some documentation for the service and that's what I got. At least now I'll be good to go when the "permanent" fix gets handed down by GM engineering and I'll have already jumped through most of the aggravating hoops. :banghead: (crossing fingers)

I had the same experience with the local Pontiac dealer. I left the car with them and they said it was normal, i mentioned the service bulletin and they said they never heard of it and looked at me like i was stupid. I ended up taking the car to the Chevy dealer and at least they looked up and tried the bulletin. It really didn't do much on my car, but its a little better. The Chevy dealer said as soon as there is a fix they will do the repair. I recieved a letter in the mail from the service manager of the Pontiac dealer saying that i would get a survey from Pontiac and if i could answer completly satisfied. After they kept my car for two days and said the vibration and rattle in the sunroof was normal. Like im going to help them out when they didn't even try to fix my car F that.

Chrisx66,

Can't say I'm surprised. It's gotten to the point where i fully expect BS when I go in for unscheduled service. There's almost an imbedded culture of incompetance or apathy that these GM dealership service departments just can't seem to shake which I feared facing after many years of Ford vehicles and excellent Ford service (which says a TON about how much I wanted and like this car! :)). Like they don't "get it" or even WANT to. :banghead: Glad to hear you found a place to get your work done though. Sad when when its a Chevy dealer and not the Pontiac dealer you bought it from.

I hear you on the survey thing. Answer honestly. The corporates DO call back with questions about any bad ratings you give and you can tell them why over the phone. My sales reps/manager made sure I was cared for and I don't doubt it has a little to do with the fact I needed service within 3 days of purchase and before I had even gotten the survey for sale of the car. I'll give sales a 100% rating on their survey but I can't say the service department was perfect on theirs.