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2008 Pontiac G8



  • rayainswrayainsw Posts: 2,582
    “I followed your Grand Prix GXP odyssey, transmission issue, etc. in that thread, and you now have a Corvette, IIRC.”

    I did have a 2005 GXP. ( Early build. ) And I did have the trans. replaced.

    I now have a 2007 Corvette with ( essentially ) the same automatic trans. that will be in the 2008 G8 GTs = the 6L80.

    Interesting ( and annoying ) to me that the trans. in my Corvette experienced a failure also. Now I hasten to add here: I do ** NOT ** in any way abuse my vehicles. Ever. Not that I don’t accelerate quickly, etc. – but I do not indulge in anything anyone cold term ‘ abuse’.

    Yet - after many, many years of driving automatics with absolutely no issues or repairs required, 2 consecutive GM vehicles have had major transmission issues – each within the first 12,000 miles.

    A few details may be of interest to those here ( and on-topic, given the G8 V8’s trans will be so similar ) regarding my Corvette’s failure:

    My 2007 Coupe had been near perfect in over 10,500 miles ( 7 months of Daily Driver \ commuter duty, as well as a couple of longer trips ) but I began to encounter a problem that seriously concerned me:

    On acceleration, at shift points, the RPM would rise significantly as an upshift executes. [ flare? ] Sounded \ felt to me ( not a trans. engineer ) like the trans. was slipping.

    This had happened to me, to a lesser degree, every once in a while over the past few months – say once a week or so. But one day, driving to lunch, it happened on something approaching half of all the shifts.

    Did not seem to matter if it was in “S” w/paddles active ( as I typically drive ) just “S” shifting for itself, or “D”. Accelerator position seemed not to be a factor.

    It happened as I drove out of my work parking lot, after sitting for over 4 hours – thus the trans. was as cool as it will be in 80+ degree weather. The trans. temp typically tops out at 207 on the stop-n-go portion of my commute home, and it did not seem any worse ( or any better ) on that drive than earlier when the trans. was cooler.

    Once in any gear, things seem fine. Meaning: The TCC unlock \ lockup appears to be working fine & downshifts appeared unaffected – no unexpected RPM fluctuations. Though it was still intermittent, I called my dealer and scheduled an appointment for the next Monday.

    A couple of days later ( a Saturday, of course ), after a couple of apparent shift attempts with long neutral between gears, the trans. stuck in second gear. And the CEL lit, at the same time. ( I was afraid that before the end of that drive, I might end up with a ‘box “full of neutrals” . . . ) Parked it.

    On Monday AM, after another few shift problems, the trans. locked in third gear – and I continued directly to my Dealer.

    I stuck to relatively rural roads, kept my speed under about 50 ( about 2,500 RPM ) and made it without further incident to my Dealer. But not much fun.

    When I received the car back ( after a week ) it shifted as new.

    Some details \ specific from the Repair Order:

    CAUSE: P0700 P2724 P2715
    1 24238968 VALVE ASM, CONT SOL
    1 24236927 F-SEAL KIT
    1 24236931 F-FILTER KIT
    7 FLUID
    FC: 180FA
    PART#: 24238968
    COUT: 10

    OBD II Codes:
    P0700 - Transmission Control System Malfunction
    P0700 Transmission Control System (MIL Request)
    P2724 Pressure Control Solenoid "E" Stuck On
    P2715 Pressure Control Solenoid "D" Stuck On
    . . . from a couple of Web sources . . .

    It took 5 business days for all the parts to arrive – and less than an hour on a lift for the actual repair.

    This was particularly annoying to me, since I had waited for a 2007 – after the 6 speed automatic trans was introduced for model year 2006 on the Corvette – specifically hoping that any potential issues with the transmission would be resolved, before mine was built.
    [[ sigh ]]

    Yet the G8 V8 ( another GM product, with virtually the same trans. that failed on me a couple of months ago ) remains at or near the top of my list as a possible replacement for the Corvette – when that time comes . . .

    - Ray
    Not necessarily always ( ever? ) logical – when it comes to cars . . .
  • bryanbryan Posts: 217
    "Not necessarily always ( ever? ) logical – when it comes to cars . . ."

    I would worry if you were ;) I don't think many "logical" people hang on these boards. That's what makes it so fun.
  • jpstax1jpstax1 Posts: 197
    Awesome guide! Thanks for the link.
  • corvettecorvette United StatesPosts: 4,222
    There is an ad on the left side of the page for the Pontiac Grand Prix, advertising 303 HP in one part of the animation, then 30 highway MPG in another part... Pretty misleading, as those aren't with the same configuration!
  • qbrozenqbrozen Posts: 17,691
    Pretty typical. I see it all the time in car commercials on TV or ads in the magazines.

    '13 Stang GT; '15 Fit; '98 Volvo S70; '14 Town&Country

  • rayainswrayainsw Posts: 2,582
    Pontiac Beefs Up High-Performance Offerings With New 2008 Torrent and G6 GXPs
    Date posted: 08-02-2007

    DETROIT — General Motors revealed details of what's to come with the new Pontiac G8 performance sedan this week, saying the lineup will "offer a V6-powered base model and a V8-equipped GT model." The Pontiac G8 is the automaker's first North American application of GM's new global rear-wheel-drive architecture. It will arrive in showrooms in January.

    - Ray
    Who had hoped to test drive one a little earlier.....
  • eliaselias Posts: 1,941
    they seem to have "forgotten" to offer a manual transmission on the G8. maybe for 2009?
  • actualsizeactualsize Santa Ana, CaliforniaPosts: 265
    What? Where do they say THAT?

    Twitter: @Edmunds_Test

  • rayainswrayainsw Posts: 2,582
    GM said, back in February, that a 6-speed manual would become available for the V8 - just would not be available in N.A. right at launch:

    "The G8 GT is powered by a uniquely configured 6.0L small-block V-8, rated at 362 horsepower (270 kW) and 391 lb.-ft. of torque (530 Nm). A six-speed automatic transmission with manual shift mode is standard and features the fuel-saving Active Fuel Management system, which enhances fuel economy by alternating between eight- and four-cylinder power. An optional six-speed manual transmission will be available soon after launch." x.html
  • nojetsnojets Posts: 31
    I would LOVE to buy this car when it is released, preferably they way it looks in the UK or Australia without all the Pontiac ticky-tacky bits GM insists on here in the US. BUT most of all, what will kill sales of the G8 in this country, and will send ME running from the Pontiac dealer in frustration, is if they put the bloody fuel tank in the trunk again, giving the vehicle less load carrying capacity than a Hollywood starlet's handbag on Oscar night. Oh GM, hear my plea, and figure out the crash regulations with some engineering, not a "workaround"!
  • qbrozenqbrozen Posts: 17,691
    if they put the bloody fuel tank in the trunk again

    Huh? How many sedans DON'T have the fuel tank in the trunk? Where else would you put it? There is certainly no room under the hood with the engine, nor under the floor of the passenger compartment. Under the trunk is all that's left. It is/was in the trunk of my Alfa, Bimmer, Accord, Lincoln, Mustang, Benz, etc.

    '13 Stang GT; '15 Fit; '98 Volvo S70; '14 Town&Country

  • rayainswrayainsw Posts: 2,582
    If your concern is primarily safety, the Holden Commodore ( the G8 will have no significant structural changes from the Australian basis ) design places the fuel tank under the rear seats, and well away from a rear end impact.

    “Holden introduced several safety initiatives in the design of the new Commodore, including relocating the fuel tank in front of the rear-axle line, instead of behind.”

    If your primary concern is the trunk size, capacity & access..
    ( vs GTO?)

    The picture with the trunk floor raised shows that the spare tire well is under there . . .

    I believe that the G8 will have a ‘saddle’ arrangement for the fuel tank – much like that in my Corvette. It is actually 2 tanks, one on each side of the driveshaft ( or torque tube ) and interconnected.

    Capacity is quoted as 19+ US gallons.

    - Ray
    Not concerned about this . . .
  • actualsizeactualsize Santa Ana, CaliforniaPosts: 265
    How many sedans DON'T have the fuel tank in the trunk? Where else would you put it? There is certainly no room under the hood with the engine, nor under the floor of the passenger compartment.

    Most, actually. Under the rear seats is popular. Most cars are front-wheel drive, so there isn't a driveshaft to deal with. Plenty of space under the rear seat but ahead of the rear axle.

    Rear wheel drive cars that also have independent rear suspension, like the G8, do have a driveshaft to deal with, but its not moving up and down with the axle. So they can use an under-seat "saddle tank" that bridges the driveshaft.

    And then there's the Honda Fit, a tiny car that puts its tank under the FRONT seats. Does wonders for cargo volume in the back. Well protected too.

    Twitter: @Edmunds_Test

  • qbrozenqbrozen Posts: 17,691
    It may START under the rear seat, but I don't think it is entirely located there. I'm pretty darned sure you'd find it is under the trunk, as well. I don't believe a 20 gallon tank would fit under the rear seat of my Accord. I'd have to get under to check, but I'm willing to bet it is both.

    The Fit's tank is entirely under the front seats? How is that possible? I mean, where do the rear passengers put their feet? And where is the filler neck?

    '13 Stang GT; '15 Fit; '98 Volvo S70; '14 Town&Country

  • hammen2hammen2 Posts: 1,313
    It is saddle-style under the rear seats. The GTO "gas tank in the trunk" was a band-aid solution until the next-gen car (VE Commodore/G8) could come out with the gas tank in front of, rather than behind, the rear axle. Holden "used to" pretty much be on their own and engineer their vehicles exclusively for Australia/maybe the Middle East. One of the things the GTO program did for Holden was force them, going forward, to follow GM standards for vehicle integration/testing (i.e. cold weather, regulation, wheel standards, et. al.), making it far easier for Holden to export cars anywhere GM needs them to.

    Any more questions?

    I, too, like the Commodore front end much better than the G8 front. However, unlike the GTO, not only will you have to change the front fascia, but also the hood. The GTO could get the Monaro front parts for ~$1400 + paint and install - I expect this to be significantly more expensive for future G8 owners (like myself) who would like to make the swap...

  • rayainswrayainsw Posts: 2,582
    My Corvette has an 18 gallon tank of very similar configuration – between the rear mounted transmission, final drive, exhaust pipes, mufflers & suspension - and the rear of the seats.

    Looking at this . . . /1003

    One might wonder exactly where there is room for those two 9 gallon tanks . . .
    The C6 is relatively ( relative to the G8 ) short & low.
    They are there.
    - Ray
    Trust me ( heh )
  • qbrozenqbrozen Posts: 17,691
    but that's different. You are talking behind the seats, correct? Not below them. I can see where they would fit in those pics you provided.

    '13 Stang GT; '15 Fit; '98 Volvo S70; '14 Town&Country

  • hammen2hammen2 Posts: 1,313
    I have an Australian book regarding the development of the VE platform. It's called "Biography" and it's by Australian automotive journalist Peter Robinson:

    It has a CAD drawing of the exact tank location on the VE Commodore. I'll try to remember to bring it to work with me tomorrow to scan in the illustration and answer this question once and for all.

  • corvettecorvette United StatesPosts: 4,222
    My Corvette has an 18 gallon tank of very similar configuration...

    First thought that came to mind was: Is it under the back seat too? :P
  • rayainswrayainsw Posts: 2,582
    Well – in looking at the pictures of the red G8 GT, the one thing that I found most disturbing ( beyond the fact that I still dislike the styling of the tail lights – but that’s very subjective ) is seeing the console shifter & the ‘manumatic’ layout.

    “+” upshift is back and “-“ downshift is forward.

    Like BMW – but the opposite of all the other sport sedans I have driven with this feature . . .

    Odd & annoying – to me.

    Oh, well . . .

    I certainly do not mean to say ( or imply ) that this is right or wrong, just opposite what I am used to - and what every other manufacturer seems to be doing.

    Even within GM, in their brand new 2008 CTS uses + \ upshift = press forward.

    From the 2008 CTS Owners Manual:

    “To enter the DSC mode, press the shift lever
    forward to upshift or rearward to downshift.”

    Again – this just seems very odd, to me.
    - Ray
    Wondering if production G8s will match the new CTS????
  • actualsizeactualsize Santa Ana, CaliforniaPosts: 265
    It may START under the rear seat, but I don't think it is entirely located there. I'm pretty darned sure you'd find it is under the trunk, as well...
    The Fit's tank is entirely under the front seats? How is that possible? I mean, where do the rear passengers put their feet? And where is the filler neck?

    The undertrunk area of most cars has a spare tire well. Ahead of that is the suspension subframe. There's more space under a rear seat than you might think.

    As for the Fit, scroll through this to see a graphic. Rear passengers have their toes near the tank, the filler neck is really long and the fuel door is in the usual location.

    Twitter: @Edmunds_Test

  • qbrozenqbrozen Posts: 17,691
    Thanks for the link. Man, that is really strange on the Fit. I wonder where the filler neck routes, and how much fuel sits in it, and if that fuel every actually reaches the tank. I mean, where does it route? If under the floor, it then needs to arch back up to the top of the tank, making it impossible for all the fuel to ever actually go in the tank. Very weird. You've piqued my curiosity.

    As for the location of the tank in trunks, as I said, I've had the tank in the trunk in most of my cars that I know of, so I don't see what the big deal is. Some have been closer to the rear of the car than others, sure, but since I don't live in the world depicted by CHiPs, I don't worry one bit about it. ;)

    FYI. The closest one to the rear I can recall was my '66 Mustang.

    '13 Stang GT; '15 Fit; '98 Volvo S70; '14 Town&Country

  • bumpybumpy Posts: 4,435
    The Fit has the tank under the front seats so Honda could do that "magic seat" thing with the second row. Gas tanks under the trunk have been unlawful in the US for a while now, which is why the GTO had to have it in the trunk (the Crown Vic & Co. were grandfathered in).
  • qbrozenqbrozen Posts: 17,691
    OH. Is this an "under" vs "in" thing? I had no idea.

    How long has "under" been unlawful? I'll have to check my Accord (if so inclined) to see where exactly it is.

    '13 Stang GT; '15 Fit; '98 Volvo S70; '14 Town&Country

  • actualsizeactualsize Santa Ana, CaliforniaPosts: 265
    Its not so much that under-trunk tanks are specifically prohibited, is it? Most automotive regulations set minimum performance standards, but try to remain "technologically neutral".

    Passing FMVSS 302*, a rear impact test designed to check for fuel leakage after crashes, has proven impossible with such a tank, so this design has died out. If a carmaker wanted to put a racing style-fuel bladder in an under-trunk design, they could pass the test. But it would cost way too much.

    *A 50-mph rear-end barrier test with no significant fuel leakage allowed after the test. They invert the car after the impact to make sure it didn't crack along the top.

    Twitter: @Edmunds_Test

  • hammen2hammen2 Posts: 1,313
    I couldn't find the CAD image of where the gas tanks are on the VE's (I know I've seen it), but below is a pic taken of VE's lower rear structure. I believe the tanks are the plastic on either side of the driveline tunnel (i.e. propeller shaft), under the rear seats...

  • actualsizeactualsize Santa Ana, CaliforniaPosts: 265
    Is this prototype shot from Lang-lang? Do we have a spy in our midst? Got any more?

    Twitter: @Edmunds_Test

  • rayainswrayainsw Posts: 2,582

    Almost at the bottom of the page.
    Part 2 at approx. 3:48 shows installation of the fuel tank.
This discussion has been closed.