6 speed auto in 4th Gen?

**matthijsgrit** · 10-05-2009, 01:41 AM

I was wondering:
what will it take to swap my 4 speed auto for a modern 6 speed, like the 6L80?
Can it be done?
Should I or should I not want this?

Mg

**mark21742** · 10-06-2009, 01:44 AM

I've wondered tge same thing about my 04 GTO.
I know in the hptuners program there are some settings for 5th and 6th gear

**JaycenK** · 10-06-2009, 10:51 AM

Mechanically I can't imagine that the motor side stuff would be all that different because it is an LSX motor it comes on. Only thing you may need is a different controller, mod the trans braket, resize the drive shaft and maybe change the input yoke. The TC, flex and pump shaft length should be spot on.

**c5z28** · 10-06-2009, 10:54 AM

They do sell a kit from a corvette. Do not know the name of the company but it can be done.

**matthijsgrit** · 10-06-2009, 11:07 AM

thanks so far, more info is welcome!
What would it mean performance-wise (accelleration, top speed) and in terms of fuel consumption?

**c5z28** · 10-06-2009, 11:11 AM

Not really sure, all I know is there optional 2.73 gear would make our stock 3.23 a little faster. I would have to imagine better gearing but I am going to have to look that info up.

**mark21742** · 10-06-2009, 04:26 PM

Originally Posted by matthijsgrit

thanks so far, more info is welcome!
What would it mean performance-wise (accelleration, top speed) and in terms of fuel consumption?

if I am correct the 6 speed gives you a steeper 1st gear, slightly closer gear ratio, so you get to keep the motor at peak power better and turn lower rpms in 6th

a6 ratio's
(1st) 4.484
(2nd) 2.872
(3rd) 1.842
(4th) 1.414
(5th) 1.000
(6th) 0.742
(reverse)2.88

a4 ratio's
(1st) 3.06
(2nd)1.63
(3rd) 1.00
(4th) 0.70
(reverse) 2.29

**Lanaue** · 10-06-2009, 04:38 PM

I was looking into doing the same to my 3rd gen Z28. Just give them about 6-8 months and someone will have a kit.You know it's been asked.

**c5z28** · 10-06-2009, 04:43 PM

Originally Posted by Lanaue

I was looking into doing the same to my 3rd gen Z28. Just give them about 6-8 months and someone will have a kit.You know it's been asked.

There is a kit it even comes with those paddle shifters-I just don't know the name.

**mark21742** · 10-06-2009, 04:54 PM

with the 4.484 1st gear, you wouldn't need 411's would you lol

**c5z28** · 10-06-2009, 06:34 PM

Originally Posted by mark21742

with the 4.484 1st gear, you wouldn't need 411's would you lol

You wouldn't want 3.73's

**JaycenK** · 10-08-2009, 07:27 PM

Originally Posted by c5z28

You wouldn't want 3.73's

Well.... I have a 2007 tundra and it has a 5 speed auto and one of the things that caught my attention was the 4.10 rear gear and the 3.8X first gear. It is wild but works out great any more gear and it would be a waist but that is just right for the power of the 4.7 motor and the wieght of the truck for what it needs to do. I would say your right about the 4.10's but depending on the power you are making 3.73's may be right on the money. If you make more power I would say 3.23 or 3.50 or so would fit better but then it still depends on engine setup. boost motors like less gear because they have a chance to build full boost before a shift point. Cool Idea though

**SHines-IT** · 10-09-2009, 06:31 PM

Originally Posted by c5z28

There is a kit it even comes with those paddle shifters-I just don't know the name.

I saw this somewhere to, it's saved on an old computer, but I got mad and broke it.

**c5z28** · 10-09-2009, 07:51 PM

Originally Posted by SHines-IT

I saw this somewhere to, it's saved on an old computer, but I got mad and broke it.

?

**346ci** · 10-09-2009, 11:36 PM

I think the swap would be quit involved as the 6L80 has an internal TCM in the valve body controlling it. Where as the 4th gens has a PCM controlling the trans. I dont think you could tie in the 6L80's TCM with a 4th gen PCM, much less there being a way to tune it.

Unless there is some aftermarket conversion kit I am unaware of, I think you would need an ECM and harness that is compatible with the 6l80's TCM, such as one from an LS3 that is designed to operate with that trans. I could be wrong, but I think it may be more headache and cost than it's worth.

**mark21742** · 10-10-2009, 05:21 PM

Originally Posted by 346ci

I think the swap would be quit involved as the 6L80 has an internal TCM in the valve body controlling it. Where as the 4th gens has a PCM controlling the trans. I dont think you could tie in the 6L80's TCM with a 4th gen PCM, much less there being a way to tune it.

Unless there is some aftermarket conversion kit I am unaware of, I think you would need an ECM and harness that is compatible with the 6l80's TCM, such as one from an LS3 that is designed to operate with that trans. I could be wrong, but I think it may be more headache and cost than it's worth.

I know there are companies that offer tranny controllers for the 4l60e in older cars for $400-$600, I'm sure they have them for the 6 speed too

**Cutlass** · 10-11-2009, 07:47 AM

Google a company called Speartech

**Cutlass** · 10-11-2009, 07:56 AM

I did some research and it seems that its most common to get a engine control module that is compatible with the existing trans module built into the 6L80e. Sounds like the 6L80e's shift setup and controls are very complex.

**JaycenK** · 10-14-2009, 08:27 PM

Originally Posted by Cutlass

I did some research and it seems that its most common to get a engine control module that is compatible with the existing trans module built into the 6L80e. Sounds like the 6L80e's shift setup and controls are very complex.

Sorry cutlass I have read that statement and for some reason I just cant figure it out. Are you saying that you can get a Factory ECM that can control the 6L80E and the Ls1's in an F body? or that you need an after market companies controller for both engine and trans? or did I just flat out have a brain fart and misunderstand that all together?
I may be loosing it

**mark21742** · 10-14-2009, 10:15 PM

Originally Posted by JaycenK

Sorry cutlass I have read that statement and for some reason I just cant figure it out. Are you saying that you can get a Factory ECM that can control the 6L80E and the Ls1's in an F body? or that you need an after market companies controller for both engine and trans? or did I just flat out have a brain fart and misunderstand that all together?
I may be loosing it

stock computer out of a car that came with an a6 would work.
you'd probably need the matching wiring harness too