This was posted in another thread. I haven't looked into the details, does anyone here have anything they can add?

 

That would be a god send!!!

 

wow...that is very interesting

 

I wonder how that's even possible.

 

i wonder what the retail is for one of those

 

too bad it is still only a four speed

 

I'm still calling BS!

 

Hard to imagine a 4-speed could handle that much power, right off the showroom floor

 

Considering thats above a 4L80E rating and is in Allison territory, i'd say its a typo. I also find it hard to believe that GM would build a new trans and keep it a 4spd. The have developed a few new 5spds, but nothing strong enough for the vette.

 

I believe that the writer of that article was not listening very closely and did not take good notes. The truth is that while the 4L60E can only handle 360 lb-ft of engine torque and therefore has torque management programmed into the C5 PCM to help keep it alive, the 4L65E is only modestly improved to handle an additional 20 ft-lb of engine torque, which means the C6 will also need torque management in order to stay alive with the LS2.

Where did the 670 ft-lb torque figure come from? It did not come out of thin air; it is the gearbox torque rating assigned to the 4L65E by the GM Hydramatic people. This compares to the 610 ft-lb gearbox torque rating of the 4L60E: http://www.gm.com/automotive/gmpower.../apps/4l60.htm

Perhaps one day GM will stop counting pennies and put a 4L80E/4L85E in the Corvette but I wouldn’t bet on it. I am sure they plan on putting a 5-speed auto in the Corvette soon but I would also bet it will come with torque management in the PCM in order to survive the warranty period

 

my bubble just burst

If it is too good to be true, then something must stink.

 

for a tranny to take that much abuse its gonna be quite heavy duty and take up mucho hp.

i thought i read somewhere about them wanting to put a 6 speed auto in? something about it was easier to do a 6 speed auto than a 5 speed auto.

 

It's got to be something new. It is definately NOT a 4L60-E, that's just beyond impossible unless GM thinks 25k mile is an acceptable life span for the trans. I think the 4L85-E components could easily take that kind of torque in production with upgraded friction materials. The problem with the 4L80/85 is that it doesn't have a removable bellhousing and therefore does not lend itself to a divorced/torque-tube application. It would need to be a new case. Maybe the new 4L80/85 trannies will get a third case design and become as versative as the 4L60-E did.

 

You are probably right. While the 2005 C6 will have to make do with the 4L65E, GM's Strasbourg plant which produces the 5L40E is planning to start production of a 6-speed auto in 2006: http://media.gm.com/servlet/GatewayS...138&docid=4177

 

A couple of days ago, I received my copy of "Corvette Quarterly" magazine. On page 65, Steve Ford, Assistant Chief Engineer for the 4L65E transmission, is quoted as saying the 2005 C6's automatic 4 speed tranny will handle a "whopping 670 lb. ft. of input torque". He then goes on to point out that the tires will light up before you can put all that power into the trans. You don't say, Steve...so the tires are saving the tranny from blowing??? What about drag radials???
Earlier in the article, you can see that all the talk is stemming from the upgrade in the 4L65E to 5 pinion planets, and what additional torque capacity they have.

I have 5 pinion planets, and I have already had to rebuild mine again, and I have more HP internal parts than the 4L65E. Those pinion gears are nice, but they won't change the fact this tranny runs on bands.

 

I think it's a play on words... The 360 rating is engine torque, 670 is input torque.

Engine torque - right off the flywheel.

Input torque - engine torque after the converter, on the input shaft. (Think STR... )

 

Here is something I got from another site.
Here is a link to the thread.
http://www.gsfcc.com/phpBB2/viewtopic.php?t=5840

 

That's interesting. I can't help but wonder if it's a misunderstanding based off the first article here.

My motor is rated at 380ft/lbs (flywheel) stock. With a factory STR of about 1.7 (right?), my 4L65's input shaft is looking at 646ft/lbs.

 

We can only hope that what is said in Corvette Quarterly is true. The 4L60E (and their clutch packs) are definitely the weaker link in the Corvette drivetrain.

If that new tranny costs less than $2500 or so, I'm gonna buy one!

 

Me too!

I'm looking to delete my four wheel drive, and go with a 4L80 when the 4L65 goes.