6 speed auto trans
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Le Mans Master
Joined: Mar 1999
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From: delmont pa
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6 speed auto trans
go to www.gmpowertrain.com ,click on transmission and check the chart about the new 6 speed auto compared to the 4 speed auto. when used with a 2.73 rear gear it shows .7% better fuel milage and 5.2% better performance BUT when compaired to the 4 speed auto with 3.15 rear gear it shows 2.6% better milage BUT 2% LESS performance. that is what i have been posting the trans is for better milage and emissions not performance.
☠☣☢ Semper Ebrius ☢☣☠
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From: Virginia
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St. Jude's Donor '06
Originally Posted by RWSjr
What would the #'s be if the 6-speedauto had a 3.15 rear gear? I'd think economy would as good or better but there would be better performance with the 6 speed auto. IMO.
With 3.15:1 the 6-speed gets 0.02 sec better 0-60 times.
With 2.73:1 the 6-speed gets 0.3 sec better 0-60 times.
But it appears that the 6-speed will only be offered with a 2.56:1 ratio, which gets worse performance than the 4-speed with a 3.15:1
Last edited by Scissors; Mar 24, 2005 at 12:51 PM.
Le Mans Master
Joined: Mar 2000
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From: Tobacco Road NC
I'm not sure the current 6 speed will take anything more than a 2.73. Going to a 3.15 with the torque of the 400 cid may be too much for the design. It's one thing to put it behind a big six or DOHC V8, and another to stick it behind 400ftlbs. Just a guess. 
☠☣☢ Semper Ebrius ☢☣☠
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From: Virginia
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St. Jude's Donor '06
Originally Posted by catbert
I'm not sure the current 6 speed will take anything more than a 2.73. Going to a 3.15 with the torque of the 400 cid may be too much for the design. It's one thing to put it behind a big six or DOHC V8, and another to stick it behind 400ftlbs. Just a guess.
Racer
Joined: Nov 2004
Posts: 325
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From: Philadelphia PA
If I like the new 6spd auto I'm planing on changing the rear. I'll either put a 3.15 or 3.42 rear in, the only problem with the 3.42 is that 1st gear is ridiculously short in the new 6spd auto, and the effective ratio spread increases... The 6spd auto with the 3.42 should get about the same mpg (a hair worse) as the 4spd auto with a 3.15.
The only other thing I would do if I get the 3.42 would be to raise the rev limiter.
The only other thing I would do if I get the 3.42 would be to raise the rev limiter.
Drifting
Joined: Dec 2004
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From: Berkeley CA
Originally Posted by clem zahrobsky
go to www.gmpowertrain.com ,click on transmission and check the chart about the new 6 speed auto compared to the 4 speed auto. when used with a 2.73 rear gear it shows .7% better fuel milage and 5.2% better performance BUT when compaired to the 4 speed auto with 3.15 rear gear it shows 2.6% better milage BUT 2% LESS performance. that is what i have been posting the trans is for better milage and emissions not performance.
Thanks for the info.
Instructor
Joined: Feb 2005
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What am I missing here?
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
Here's a picture of my 442 (sold around 1978) - my luck with pictures hasn't been exactly great so I hope it can be seen.
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
Here's a picture of my 442 (sold around 1978) - my luck with pictures hasn't been exactly great so I hope it can be seen.
Last edited by AAMC6; Mar 24, 2005 at 09:38 PM. Reason: insert picture
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☠☣☢ Semper Ebrius ☢☣☠
Joined: Jun 2001
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From: Virginia
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St. Jude's Donor '06
Originally Posted by AAMC6
What am I missing here?
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
One is that a shorter rear axle ratio is actually easier on the transmission.
Two is that GM isn't saying that the transmission can't handle a shorter rear end. All GM states, and it's very clear, is that the 6-speed's greater efficiency results in the need for only one rear axle ratio rather than two in order to meet performance and fuel economy targets. The 4-speed wasn't efficient enough to meet both targets using just one rear axle ratio.
Team Owner
Joined: Feb 2001
Posts: 27,254
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From: Short Hills, NJ
Originally Posted by Scissors
All GM states, and it's very clear, is that the 6-speed's greater efficiency results in the need for only one rear axle ratio rather than two in order to meet performance and fuel economy targets. The 4-speed wasn't efficient enough to meet both targets using just one rear axle ratio.
Keep in mind that, just like the rumor/announcement that 2006 will bring the new 6 speed auto, the info on the rear is ALSO preliminary right now, we don't know for just yet. Maybe they will offer an optional axle ratio for the new trans or maybe the 2.73 will be the sole rear gear and not the 2.56...we'll know in a few months I hope.
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Le Mans Master
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From: delmont pa
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Originally Posted by LS1LT1
Do they even actually state that or is it just implied because that's what the chart shows?
Keep in mind that, just like the rumor/announcement that 2006 will bring the new 6 speed auto, the info on the rear is ALSO preliminary right now, we don't know for just yet. Maybe they will offer an optional axle ratio for the new trans or maybe the 2.73 will be the sole rear gear and not the 2.56...we'll know in a few months I hope.
Keep in mind that, just like the rumor/announcement that 2006 will bring the new 6 speed auto, the info on the rear is ALSO preliminary right now, we don't know for just yet. Maybe they will offer an optional axle ratio for the new trans or maybe the 2.73 will be the sole rear gear and not the 2.56...we'll know in a few months I hope.
☠☣☢ Semper Ebrius ☢☣☠
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From: Virginia
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St. Jude's Donor '06
Originally Posted by LS1LT1
Do they even actually state that or is it just implied because that's what the chart shows?
Race Director
Joined: Oct 2004
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Originally Posted by AAMC6
What am I missing here?
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
Instructor
Joined: Feb 2005
Posts: 222
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Originally Posted by shopdog
Who said they were having trouble making an A6 tranny to handle the torque? If they are having troubles, and I don't know that they are, it would be because this is a brand new, and very complex, design. As with any totally new auto transmission, there are often teething problems before they get it right. The Turbo Hydramatic turned out to be a very good transmission, but not the very first ones. It took several incremental improvements over the years to make it as tough and reliable as it ultimately became.
Thread Starter
Le Mans Master
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From: delmont pa
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Originally Posted by shopdog
Who said they were having trouble making an A6 tranny to handle the torque? If they are having troubles, and I don't know that they are, it would be because this is a brand new, and very complex, design. As with any totally new auto transmission, there are often teething problems before they get it right. The Turbo Hydramatic turned out to be a very good transmission, but not the very first ones. It took several incremental improvements over the years to make it as tough and reliable as it ultimately became.
Team Owner
Joined: Feb 2001
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From: Short Hills, NJ
Originally Posted by AAMC6
I've seen it mentioned in other threads.
Burning Brakes
Joined: Aug 2004
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From: Folsom Ca
Originally Posted by AAMC6
What am I missing here?
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
Here's a picture of my 442 (sold around 1978) - my luck with pictures hasn't been exactly great so I hope it can be seen.
In 1970, I had an Olds 442 W-30 that had 365 bhp and 500, yes 500 ftlbs of torque. I added a crane cam, edlebrock manifold, hooker headers, etc, so the engine was making even more power and torque.
The car had a 3 speed turbo hydramatic (I think they called it) and a 3:91 rear end. No transmission problems.
35 years later, GM is having trouble making a 6 speed that will handle 400 ftlbs of torque w/a 3:15 rear? This is all due to the 3 extra gears?
Here's a picture of my 442 (sold around 1978) - my luck with pictures hasn't been exactly great so I hope it can be seen.
The Vette current '05 trans was derived from the Turbo 350, went to overdrive as the 700R4, then electronically controlled as the 4L60E and finally for performance applications like the Vette, was beefed up a bit internally and is now the 4L65E.
The strength of the transmissions is dependent upon the size, materials, and design of the internal components.
GM has had some very unstout autos since your W30 442, such as the Turbo 180's that were junk. Olds and Pontiac in the later years models offered an overdrive trans that was called the 200R4. Pretty good when worked over with some heavy duty internals. But, GM didn't think enough of it to use in the Trans Am of late with the Chevy LT1 or LS1's, they got the 4L60E.
Team Owner
Joined: Jun 2001
Posts: 26,714
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From: Houston, TX
Clem, I guess you'll need to paint me a picture. I cannot find the chart. Under "transmission", there are several other choices. Can you give me more info on where to find the chart?
Thanks
Thanks
Team Owner
Joined: Feb 2001
Posts: 27,254
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From: Short Hills, NJ
Originally Posted by jschindler
I cannot find the chart. Under "transmission", there are several other choices. Can you give me more info on where to find the chart?
http://www.gm.com/automotive/gmpower...rwd_6speed.pdf
Racer
Joined: Nov 2004
Posts: 325
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From: Philadelphia PA
After reading about the different 6spd auto variations it looks like the only difference between the biggest version and the smallest is 1" in length.
If you look at the pictures from the .pdf file you can see that the X15R C and X16R D variants look to have the same "casing". My point is, when this transmission goes into the C6 it should be the X15R which means upgrading to X16R internals shouldn't be a problem, or switching the entire X15 for the X16.
Adding a Magnuson SC (low boost 500HP) and a 2.73 or 3.15 rear to the X16R D would make the C6 incredible. I'm planning ahead
If you look at the pictures from the .pdf file you can see that the X15R C and X16R D variants look to have the same "casing". My point is, when this transmission goes into the C6 it should be the X15R which means upgrading to X16R internals shouldn't be a problem, or switching the entire X15 for the X16.
Adding a Magnuson SC (low boost 500HP) and a 2.73 or 3.15 rear to the X16R D would make the C6 incredible. I'm planning ahead
