OK guys, I have read in countless places that the 6L80E (A6) is only rated for 430 ft.lbs(rating is for engine torque not rwtq.). Yet I see guys modding and running 500ft./lbs.(RWTQ) and more. I have seen people say not to heavily mod a car with an A6, and I've seen people say that it can take all you can throw at it. I understand that the "rating" does not necessarily mean thats all it can handle, but it is there for a reason.

So what the deal on this trans? If I throw a maggie on mine will I have problems? What torque are you modded guys running and for how many miles? Any problems? Thanks for the responses.

 

I have about 485TQ and it's been about 3000 miles with no probs so far!!
Good luck!

 

APS (the turbo company) told me 500 rwtq is all it can handle, but I, too, have heard of others running more power than this, all without issues.

 

A GM Representative at Carlisle, in 2006, while answering questions about the A6 (6L80) transmission, reportedly said, "The A6 was designed to withstand the 650 lb. ft. of torque of the Duramax Diesel, and they had tried to break the A6 transmission, with no success." His final words were, "You don't have to worry about the C6!"...

 

i hope this is true im debating on getting an a6 o7

 

fastgt350, Just to add further information, I have a 2007 C6 A6 with paddle shift, I have a Lingenfelter 427 CID motor making 472.1 RWHP, and 484.8 RWTQ, drive it aggressively, every day, with no problems. When you do get your '07 A6, you might think of upgrading your differential, if you plan on doing any modding. Enjoy your new car...

 

Two things:

1: The Duramax doesn't use the 6L80E. It uses an Allison 1000. Completely different transmission, and MUCH more durable than the 6L80E could ever think about being. The maximum gearbox torque capacity of the Allison 1000 is 900 lb/ft.

2: The Duramax spins to approx. 3500 rpms from the factory, not up to 6500 rpms like the LS2/LS3 Vettes.

 

If you wil look the 6L80E is used in the STS-V rated Tq on that engine is 439Lbs, I do not think GM would exceed their own specs. I think they want a wide margin and 430 is not what the torque figures are for the one used in the STS-V and I doubt that is the figure in the Corvette, being many members have exceeded that number with no problems. Don't we have any GM techs on this board that have been trained on this transmission that could tell us actuals ?

 

He didn't say it's used with the Duramax. GM used the Duramax to test the 6L80 and couldn't break it. Torque is torque as far as force is concerned, RPM is not a factor.

The old Turbo 400 was renamed the 3L80 when GM went to a relative rating system with the higher number representing higher torque capacity. They added overdrive to it and it became the 4L80. While the 6L80 doesn't share anything with either of those transmissions, it has the same relative torque capacity...and the Turbo 400 was used behind high performance big blocks with mountains of torque. Zora Duntov had a ZL1 600+ HP big block '69 'Vette with a turbo 400 that could click off 10 second 1/4 mile runs all day long...and that was in '69 when a 10 second 1/4 mile was phenomenal.

APE doesn't say 500 LB FT is the limit of the 6L80, they say the 6L80 will have no problem handling the 500 LB FT of their turbo kits. It doesn't mean the 6L80 will catastrophically fail at 501 LB FT. Long term reliability begins to be impacted at levels exceeding 500 LB FT...so instead of getting 200K miles, you only get 150K miles. I could live with that.

 

Thanks very much for the information on the A6 6L80 transmission, glass slipper. There has been too much negative speculation on the strength of the 6L80 A6 transmission. Lingenfelter has Corvette's with 725 to over 1000 RWTQ running around with this 6L80 A6 transmission in it's stock form for many months, with no problems at all...

 

APS specifically told me, on the phone, that anything much over 500 rwtq and the 6L80E is a ticking timebomb. APS also stated that GM wouldn't ever use the current 6L80E in a Z06, due to reliability concerns. APS may wish to clarify all of this, but this is my great recollection of our phone conversation.

FWIW, I'm not directly stating the transmission won't hold up to extreme power. I've specifically stated above that I heard (even seen) others running a great amount of power through them. I only repeated what APS told me due to obvious testing and findings on their part.

Yes, torque is torque (simple physics), but components also have a relative rpm and frictional capacity, as well. The difference between 3500 rpms and 6500 rpms is a massive exponential increase.

Sincerely,

James

 

thanks man, but would that be necessary with only around 420 440 whp?

 

Whether or not you should upgrade your differential would more depend on how you plan to drive your car,rather than the planned horsepower. If you plan on aggressive driving, track use, etc. the upgraded output shafts would be wise insurance IMO. 420-440 rwhp is 90 to 110 more than stock, so it will make a difference...

 

 

Whoever you talked to at APS was wrong if that's what they said. If it's so fragile that it becomes a "ticking time bomb at anything over 500 RWTQ", than anything 400-500 RWTQ is marginal for any kind of extended use meaning 50K miles or more...and we know that's not true or they better stop marketing their turbo kits for A6s. The 6L80 is more than capable of handling the output of the LS7 from the Z06, that is not why GM doesn't use the A6 in that application. The Z06 is an extreme supercar and the A6 does not fit in that equation. The A6 is much heavier than the M6 which would negate all the weight savings from all the aluminum, magnesium, and carbon fiber components the regular C6 doesn't have. There's also the greater HP loss through the A6. Could you imagine somebody spending all that money on an A6 Z06 just to be outrun by a C6 Z51 M6? GM would not allow that to happen. Also, GM has to certify every engine/transmission combination for emissions and fuel mileage with the EPA. They aren't going to go to the expense of doing that for such a low production run.

You are correct to look at the RPM, but that's a matter of HP causing extra heat. If the oil/coolers can keep the transmission temperatures acceptable (which it does), then it's not a concern. So RPM is a heat issue. Torque is a structural issue with the strength of the transmission determining the torque capacity.

 

Really? Give me a break. Please tell me how you figure this is possible.

 

he can't!, he just like to throw all kinds clueless data at you to get you to say you were wrong.

 

That's just because the A6 is fairly new trans and we recommed that customers don't exceed the 500 rwtq figure unless the A6 trans has been upgraded..............maybe a conservative approach though that's better than frying the auto in the short term.

Peter

 

6L80 torque spec is 670lb.ft.

 

NORTY, Can you direct us to the reference for the above 6L80 torque spec? Thanks much...