I ordered my 2006 coupe on Thursday. The dealer gave me a copy of their order guide.
The 6-speed automatic EPA mileage ratings were the same as the 4-speed for 2005. Is this because they don't have the real numbers yet, I hope? They did confirm the 2.56 differential gearing as the only one available.

The second surprise was that the transmission gear ratios were listed as "TBD", or to be determined. GM has already released the Caddy ratios for the car built in the same plant. I can't believe that the Vette will have different ratios than the Caddy. Could it be that the Chevy marketing wizzes don't read the other GM announcements? Gads, does the left hand know what the right hand is doing?

Okay it is the fact that the left hand doesn't know what the right hand is doing. I found a quote at media.gm.com that does list the first gear as the same as the Caddy. at 4.02!

Quoting:
The six forward gears have smaller “steps” between them, which enhances the feeling of performance and smoothness. The smaller steps also enable a steep, 4.02:1 first gear, which provides an improved-performance launch feel when compared with the previous four-speed automatic’s 3.06:1 first gear. There are two overdrive gears: a 0.85:1 ratio in fifth gear and a 0.67:1 ratio in sixth. The final drive ratio of Corvette models equipped with the new transmission is 2.56:1.

Quote:

"The six forward gears have smaller “steps” between them, which enhances the feeling of performance and smoothness. The smaller steps also enable a steep, 4.02:1 first gear, which provides an improved-performance launch feel when compared with the previous four-speed automatic’s 3.06:1 first gear."

Notice how the release said the new setup will "enhance the FEELING of performance..." and " "improved launch FEEL?" It will be interesting when the actual performance is known versus the "FEELING" of performance. I have high hopes, but sounds like GM is hedging their bet.

the GM powertrain web site shows that the new 6 speed auto with the 2.56 rear gear is slower 0-60 that the 4 speed auto with the 3.15 rear gear BUT better milage

|UPDATED|8/22/2005 2:22:09 PM (AZT)|/UPDATED|

ah slower by 2% is the claim. That is slower than the G90 optioned current A4 not the standard 2.73 differential. There has to be that much variation in sample to sample for the current A4 G90 option anyway.