I left work this afternoon and noted the car wasn't shifting in Drive. Took a look down and the wonderful "engine" light was illuminated. I hit the hand OnStar button to be told that my car required immediate service to the transmission and/or engine within 24 hours. I made it home driving all over 45 mph in the cripple transmission mode and will be sitting at the dealership in the morning. Wish me luck...

Good luck. This thread will get tons of viewers. This is another reason that I prefer manuals transmissions.

I left work this afternoon and noted the car wasn't shifting in Drive. Took a look down and the wonderful "engine" light was illuminated. I hit the hand OnStar button to be told that my car required immediate service to the transmission and/or engine within 24 hours. I made it home driving all over 45 mph in the cripple transmission mode and will be sitting at the dealership in the morning. Wish me luck...
Good luck. Hopefully just a bad sensor.

Wow, good luck. I know the feeling, wanting to get back behind the wheel of the G8.

Good luck bro... i know how it feels to have a brand new car in the shop (RIP 07 vortecmax)

Strange. Many times this is a bad solenoid in the valve body. Not really a big deal as far as trannys go. But that seems like it would be annoying.

That sucks, hopefully it is something simple.:D

Good luck. This thread will get tons of viewers. This is another reason that I prefer manuals transmissions.

Why's that?? Car's with sticks don't break down?? :D

Why's that?? Car's with sticks don't break down?? :D

I've had better luck with manuals.

I've had better luck with manuals.

Not me, it's no fun to replace clutches

I love automatics..

I agree, there just seems to be a lot less going on. I've built manuals, but have yet to tear into an auto.

I've had better luck with manuals.

Good luck today. Let us know how it turns out.

Strange. Many times this is a bad solenoid in the valve body. Not really a big deal as far as trannys go. But that seems like it would be annoying.

Interesting.

The 6L80 trans in my Corvette ( same designation as the one in the G8 GT ) had shifting issues – and finally locked itself into third gear.

My understanding is that this is part of the “Limp Home” mode.
Remains in third & TCC will not lock.

Here is a list of the parts replaced per the receipt:

CAUSE: P0700 P2724 P2715
PRESSURE CONTROL SOLENOID #5 STUCK ON
K6562 REPLACE TCM AND REPROGRAM PCM
1 24238968 VALVE ASM, CONT SOL
1 24236927 F-SEAL KIT
1 24236931 F-FILTER KIT
7 FLUID
FC: 180FA
PART#: 24238968
COUT: 10

Not me, it's no fun to replace clutches

But, at least most of us know what the problem is. In an AT, it could be any of a dozen different reasons. Plus, I take my vehicles to another shop to replace a clutch. :D

So, what's the verdict Blackonblack? You all set, or do you have to wait for parts?

Good luck. This thread will get tons of viewers. This is another reason that I prefer manuals transmissions. Yea never any trouble with gm's clutch hydrolics :rolleyes::rant::censored::nono:

Not good... let us know what happens

Yea never any trouble with gm's clutch hydrolics :rolleyes::rant::censored::nono:

Only had that happen once. Out of 4 GM vehicles with MTs, that's still a good ratio.

It ended up being solenoid code that caused the engine light and tranny to go into "limp" mode. They replaced the solenoid and told me that it was probably a shaving that caused the solenoid to hang. They changed the tranny fluid and filter at my request. I put about 500 miles on the car this weekend with no further problems.

It ended up being solenoid code that caused the engine light and tranny to go into "limp" mode. They replaced the solenoid and told me that it was probably a shaving that caused the solenoid to hang. They changed the tranny fluid and filter at my request. I put about 500 miles on the car this weekend with no further problems.

Glad they got you taken care of. Good luck with the car. Hope it doesn't give you any other problems.

fwweeeewwwwww! swapping a tranny(worst case) on your new car...what a thought

well its all good then!

It ended up being solenoid code that caused the engine light and tranny to go into "limp" mode. They replaced the solenoid and told me that it was probably a shaving that caused the solenoid to hang. They changed the tranny fluid and filter at my request. I put about 500 miles on the car this weekend with no further problems.

Glad it was taken care of quickly!!

glad everything worked out. yet it's another good reason to wait for a manual tranny.

does anyone else think that the way the tranny comes stock in these cars seems to feel like it wont last.... Im getting slipping and late changes into 6th at higher speeds.... almost as if it cant change.!! Im still trying to work it out.

I wonder... would a tune on the tranny help, not only with performance, but also with the overall life of the bloody thing??

glad everything worked out. yet it's another good reason to wait for a manual tranny.

Why is this another good reason to wait for a manual?? One guy had a problem with a $50 part???

does anyone else think that the way the tranny comes stock in these cars seems to feel like it wont last.... Im getting slipping and late changes into 6th at higher speeds.... almost as if it cant change.!! Im still trying to work it out.

I wonder... would a tune on the tranny help, not only with performance, but also with the overall life of the bloody thing??

I have still yet to experience what everyone is talking about.... I have zero complaints whatsoever with my car, and experience no slipping or slow shifting of any sorts..

me either with the slipping,taking a deap breath before slamming down 3 gears,now that happens to all of us!

me either with the slipping,taking a deap breath before slamming down 3 gears,now that happens to all of us!
Count me in with the folks experiencing slow sloppy down shifts and the taking a deep breath thing...

'Sports Mode' or 'Manual Mode' the same thing. I don't think this transmission is capable 'barking' the tires with any shift mode. It just ain't going to happen.

Glad everything got resolved man and that the problem wasn't as big as it seemed.

good thing it was nothing big

The A6 is a good transmission, used in the CTS and Vettes and engineered for 625HP. The problem with ATs is the extreme complexity and the dependence on absolutely clean assembly. Don't "dis" the A6 because one tiny bit of shaving escaped the inspection on one car. While I have no love of ATs, mine is working fine and I look forward to pushing it a bit when the car is broken in a bit more.

I sounds like I am having the same issue (at 1300 miles!!). I was driving last night and the DIC started beeping at me and locked the tranny into 3rd. I stopped and shut the engine off for a little bit (had to fill up). It shifted normally for about a mile and then went back into limp home mode. It is either a solenoid problem or computer problem. I scanned it and got the following two codes:
P0700 - Transmission Control System Malfunction
P1825 - Internal Mode Switch - Illegal Range
The dealer service dept doesn't open until 8 am today. I will request that they tow it. I do not want to try driving on Houston Freeways limited to about 45 mph.

I scanned it and got the following two codes:
P0700 - Transmission Control System Malfunction
P1825 - Internal Mode Switch - Illegal Range

What did you use to scan the codes?

What did you use to scan the codes?

My Auto X-ray 4000 scanner (I had previously bought the extended GM codes).

I sounds like I am having the same issue (at 1300 miles!!). I was driving last night and the DIC started beeping at me and locked the tranny into 3rd. I stopped and shut the engine off for a little bit (had to fill up). It shifted normally for about a mile and then went back into limp home mode. It is either a solenoid problem or computer problem. I scanned it and got the following two codes:
P0700 - Transmission Control System Malfunction
P1825 - Internal Mode Switch - Illegal Range
The dealer service dept doesn't open until 8 am today. I will request that they tow it. I do not want to try driving on Houston Freeways limited to about 45 mph.

Did you notice anything strange before this happened? Just wondering if there is something others should be looking out for.

Did you notice anything strange before this happened? Just wondering if there is something others should be looking out for.
Nothing stands out.

. . . I do not want to try driving on Houston Freeways limited to about 45 mph.

1 - Yuk - sorry to hear...
2 - If locked in third - 6,000 RPM is approx. 104 MPH.
So - you COULD drive at highway speeds -
though the RPM & MPG would not be terrific -
you'd be OK.
Unlikely the Dealer has anyone that could help much
today though, anyway...
Best of luck!
- Ray
6L80 ( in my Corvette ) similar situation within first year...

Ouch.

When I test drove a local G8 GT the tranny was a complete turn off to me. Felt very sloppy. Can't wait to test drive a manual version if they ever hit the states.

whats the fix on these problems? Is it a transmission problem or a solenoid problem?

I got it back from the dealer. They cleared the codes and could not get the problem to replicate. They wanted to let a tech take it home to put some more miles on it and I told them no, I can do that. So for now, things are fine. I honked on it several times on the way home and no issues. We will see.....

Wow this makes me nervous.. Going through all of this stress trying to figure out what to do, what color, options, calling in favors from my GM employee discount father in law and finding the car i want and then, to get a car that has tranny problems!!!


That would SUCK!!!!!!:The_Villagers::The_Villagers:

I've had all kinds of hydrolic issues with my 2006 GTO, and gone through three clutches in 45k miles, 2 stock clutches and one LS7. GM products are going down hill in terms of quality. Anyway, " why wait for the manual tranny"? because it's a heck of alot faster car. Automatics are always slower than well driven sticks, always not to mention heavier by 100 lbs too. I raced my buddy yesterday with his K'&N, full exhaust G8 GT the other day with my stock M6 2006 GTO and I put nearly 2 cars on him to 65 mph and four cars on him by 110. Pontiac always over states the performance figures to help new models sell. I've seen the actual road testing of these new G8 GT's and when you consider the math, (361 hp \385 tq, 4000lbs and a rear axle ratio under 2.93) you will have lack-luster acceleration. Pontiac overstated the GTO's to. The G8 GT does 0-60 in 5.6 sec, the new ( Fall 08' release) GXP G8 LS3 M6 will run the same feat in 4.8 sec thanks to 402 hp and 402 tq and a good short gear ratio, I think a 3.46 out of the vette, 3.42 or maybe even a 3.73, they have not decided yet. The big heavy CTS-v at 3938 lbs had a 3.73 that's why it was faster than the GTO in the quarter stock for stock.

I raced my buddy yesterday with his K'&N, full exhaust G8 GT the other day with my stock M6 2006 GTO and I put nearly 2 cars on him to 65 mph and four cars on him by 110.


Your car has 40 hp on his car (OK 35 with mods listed), and weighs 270 lb less.

How many car lengths does 35hp/270lb supposed to pull by 110?

I've had all kinds of hydrolic issues with my 2006 GTO, and gone through three clutches in 45k miles, 2 stock clutches and one LS7. GM products are going down hill in terms of quality. Anyway, " why wait for the manual tranny"? because it's a heck of alot faster car. Automatics are always slower than well driven sticks, always not to mention heavier by 100 lbs too. I raced my buddy yesterday with his K'&N, full exhaust G8 GT the other day with my stock M6 2006 GTO and I put nearly 2 cars on him to 65 mph and four cars on him by 110. Pontiac always over states the performance figures to help new models sell. I've seen the actual road testing of these new G8 GT's and when you consider the math, (361 hp \385 tq, 4000lbs and a rear axle ratio under 2.93) you will have lack-luster acceleration. Pontiac overstated the GTO's to. The G8 GT does 0-60 in 5.6 sec, the new ( Fall 08' release) GXP G8 LS3 M6 will run the same feat in 4.8 sec thanks to 402 hp and 402 tq and a good short gear ratio, I think a 3.46 out of the vette, 3.42 or maybe even a 3.73, they have not decided yet. The big heavy CTS-v at 3938 lbs had a 3.73 that's why it was faster than the GTO in the quarter stock for stock.


“Pontiac always over states the performance figures. . .”
“I've seen the actual road testing. . .”
“ . . . axle ratio under 2.93) you will have lack-luster acceleration.”
And, from another of your posts:
“Don't waste your $$ on a over weight underpowered G8 GT.”

My, my.

While some will ‘require’ quicker acceleration ( high 13s in road tests I have seen, and I have taken a short test drive ), I would not characterize the G8 GT’s acceleration as ‘lackluster’ – for a full-sized 4DR sedan. You certainly may. And Pontiacs numbers have been duplicated almost exactly by at least 3 independent publications.

The G8 GT’s acceleration is very close to the BMW 550i’s, in Automobile Magazine’s testing. Also the 550 weighs a similar amount – though the G8 is larger inside. And most people don’t consider the 550’s acceleration ‘lackluster’ – except ( perhaps ) if comparing to an M5.

‘over weight’? If any manufacturer knows a magical way to build a significantly lighter G8 sized car, with G8 GT \ BMW 550i class performance, and sell it for low $30,000s – I have not seen such a beast. And the 550i base MSRP is in the $60K neighborhood.

But you are welcome to your opinions.

- Ray
Looking quite seriously at ‘wasting my $$s’ on a G8 GT – to replace a Corvette, that does NOT have lackluster acceleration . . .

“Pontiac always over states the performance figures. . .”
“I've seen the actual road testing. . .”
“ . . . axle ratio under 2.93) you will have lack-luster acceleration.”
And, from another of your posts:
“Don't waste your $$ on a over weight underpowered G8 GT.”

My, my.

While some will ‘require’ quicker acceleration ( high 13s in road tests I have seen, and I have taken a short test drive ), I would not characterize the G8 GT’s acceleration as ‘lackluster’ – for a full-sized 4DR sedan. You certainly may. And Pontiacs numbers have been duplicated almost exactly by at least 3 independent publications.

The G8 GT’s acceleration is very close to the BMW 550i’s, in Automobile Magazine’s testing. Also the 550 weighs a similar amount – though the G8 is larger inside. And most people don’t consider the 550’s acceleration ‘lackluster’ – except ( perhaps ) if comparing to an M5.

‘over weight’? If any manufacturer knows a magical way to build a significantly lighter G8 sized car, with G8 GT \ BMW 550i class performance, and sell it for low $30,000s – I have not seen such a beast. And the 550i base MSRP is in the $60K neighborhood.

But you are welcome to your opinions.

- Ray
Looking quite seriously at ‘wasting my $$s’ on a G8 GT – to replace a Corvette, that does NOT have lackluster acceleration . . .

Check his other posts, hes a borderline troll... I doubt he'll last the week.

Wow this makes me nervous.. Going through all of this stress trying to figure out what to do, what color, options, calling in favors from my GM employee discount father in law and finding the car i want and then, to get a car that has tranny problems!!!

There are typically a few "teething" problems with any new line of cars. Based on what I have been reading from the Aussie forums, most guys are getting the M6, so the US market will have a lot more A6 out being driven. In my case, unless it comes back, it was only a software glitch (has been known to happen from time to time). I would not let these two posts deter you from considering a G8.

There are typically a few "teething" problems with any new line of cars. Based on what I have been reading from the Aussie forums, most guys are getting the M6, so the US market will have a lot more A6 out being driven. In my case, unless it comes back, it was only a software glitch (has been known to happen from time to time). I would not let these two posts deter you from considering a G8.

Do you know what codes it threw? I went back and looked but didn't see any posted. Maybe I missed it. If all they did was clear the codes you may want to look into a DashHawk. That way you could pull the codes yourself and clear them to at least run the car normally to the dealer. Unless they need to actually see it happening.

I've had all kinds of hydrolic issues with my 2006 GTO, and gone through three clutches in 45k miles, 2 stock clutches and one LS7. GM products are going down hill in terms of quality. Anyway, " why wait for the manual tranny"? because it's a heck of alot faster car. Automatics are always slower than well driven sticks, always not to mention heavier by 100 lbs too. I raced my buddy yesterday with his K'&N, full exhaust G8 GT the other day with my stock M6 2006 GTO and I put nearly 2 cars on him to 65 mph and four cars on him by 110. Pontiac always over states the performance figures to help new models sell. I've seen the actual road testing of these new G8 GT's and when you consider the math, (361 hp \385 tq, 4000lbs and a rear axle ratio under 2.93) you will have lack-luster acceleration. Pontiac overstated the GTO's to. The G8 GT does 0-60 in 5.6 sec, the new ( Fall 08' release) GXP G8 LS3 M6 will run the same feat in 4.8 sec thanks to 402 hp and 402 tq and a good short gear ratio, I think a 3.46 out of the vette, 3.42 or maybe even a 3.73, they have not decided yet. The big heavy CTS-v at 3938 lbs had a 3.73 that's why it was faster than the GTO in the quarter stock for stock.

Sounds like you don't need to be shopping for a G8 if the performance is "lackluster". Better enjoy the GTO, before Mommy takes it away from you. :gr_jest:

Do you know what codes it threw? I went back and looked but didn't see any posted. Maybe I missed it. If all they did was clear the codes you may want to look into a DashHawk. That way you could pull the codes yourself and clear them to at least run the car normally to the dealer. Unless they need to actually see it happening.


P0700 - Transmission Control System Malfunction
P1825 - Internal Mode Switch - Illegal Range


I will use my AutoXray scanner. That is what I used to pull the codes the first time. It also allows for real-time monitoring of many parameters as well as short runs of data logging.

Just had my new 09 G8 GT with 380 miles on it begin to shift erractically and then went into "limp mode" which was 2nd gear. Since at the time I was on the I-15 in St. George, Utah, I had to "limp" at around 5000 rpm until I could exit and head back to the dealer (Newby Buick, GMC, Pontiac). Will keep you posted.

Just experience a "limp mode" in 2nd gear in my 09 G8 Gt with 385 miles on it! Limped back to the dealer and am awaiting news on Monday as to what the problem is. Transmission began to slip and "hunt" just before light came on. Will keep you posted.

Does Onstar have the capability to tell you what the codes are?

Sorry Bro! You're warranty will kick in and you'll be back stabbing it in no time! I agree, probably a solenoid or something silly in the computer. Good Luck!

Does Onstar have the capability to tell you what the codes are?


Yup!

They can probably tell you if your fly is open :secret:

Yup!

They can probably tell you if your fly is open :secret:

Well, in that case, diagnosis isn't as difficult as some people are making it out to be.

OBD isn't heirogylphics guys. :eek2:

Count me in with the folks experiencing slow sloppy down shifts and the taking a deep breath thing...

'Sports Mode' or 'Manual Mode' the same thing. I don't think this transmission is capable 'barking' the tires with any shift mode. It just ain't going to happen.

thats nonsense, tune the trans and do some mods=:gears: