LB7: Allison 5 speed to 6 speed conversion

[sam_rork]

This!!! I had mine built back in April, wish I had done it years ago. It’s a different truck.

So many hard decisions haha well thanks everyone on the inputs. I do have more questions for everyone opinions. And I guess I need to find a tranny guy in my area to talk to. I’m sure Mike and Evan are great they are just really far from me. I was really only looking for opinions and options rather than a person anyway. A built transmission was gonna be my next purchase until the other day when I ran across a 6 speed conversion, this would help my highway driving. Was just a thought but thanks everyone I think I’ll go with my first thought of a rebuild!



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[Mike L.]

Call me if you need help.

 

[sam_rork]

Call me if you need help.

Thanks for the help!!! I’ll keep you in mind


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[zakkb787]

Something that all new diesel guys need to learn is that it is a completely done fervent, more expensive, more complicated and costly world than gassers could ever dream of being. Everyone tries to push their products no matter how underdeveloped they may be. Look at Sinister stuff. Look at the cheaply made knock offs of ricks pipes. Especially with fuel systems and transmissions, you really have to do your research on REPUTABLE sites, not the “other” duramax forum. Not Facebook. And not sites that advertise their own stuff. Most of the best stuff you can buy are from sites that aren’t even fully developed and up to date, or are just simple site not over promoting their own stuff. Sites like Lincoln diesel, profab, Kennedy, are just a here to sell their stuff because everyone knows their quality and doesn’t need the hype. The guys on this site can be difficult at times because we get a lot of people that want us to diagnose their problems and then leave. We do not get paid for this. It’s a hobby. So we don’t appreciate people demanding answers. Or getting cocky. Not saying you were. Not saying that at all. But most of these guys have known each other for a while and have some running jokes going.

That being said, Mike and Evan both are absolutely no questions asked the best people there are to mess with Allison’s. Listen to what they say. Don’t listen to internet BS and hype. They may be far but it’ll be worth the trip or shipping. I went local on my first Allison build and it was a hack job. And that was from the best shop around. Allison’s need precision. Not just a “kit”. I know of lots of guys that have bought Evan’s DIY kit and have had great success. That comes with Evan’s guidance too.

Sorry for the rant. Bored at work.

 

[DAVe3283]

You can have good luck getting an Allison built at a local shop. My truck's 2nd (current) transmission was done by a reputable local shop, and so far it's every bit as good as the 1st (MikeL build from when I lived in CA). But many local shops don't have the skills or knowledge to build a performance Allison, so you tend to take your chances.

We have had members successfully build their own Allison from a kit, and a few be less than successful. You have to be patient and have attention to detail. It isn't easy. We just want you to know what you're getting into here.

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[Dozerboy]

So many hard decisions haha well thanks everyone on the inputs. I do have more questions for everyone opinions. And I guess I need to find a tranny guy in my area to talk to. I’m sure Mike and Evan are great they are just really far from me. I was really only looking for opinions and options rather than a person anyway. A built transmission was gonna be my next purchase until the other day when I ran across a 6 speed conversion, this would help my highway driving. Was just a thought but thanks everyone I think I’ll go with my first thought of a rebuild!



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Look very carefully! There are a ton of shops that claim they can/will build your trans. All you end up with is a pile of junk and they got your money. I was lucky that the shop that was recommended to me by suncoast had a good reputation and some dealings with Mike which put me at ease. Other wise I would of had to ship my broke truck to someone that knew what they where doing.

Why do you want a 6speed anyways? Really that extra gear isn’t anything special. Chevy1925 is about the only guy I’ve seen that did it that was very happy with it.


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[sam_rork]

Look very carefully! There are a ton of shops that claim they can/will build your trans. All you end up with is a pile of junk and they got your money. I was lucky that the shop that was recommended to me by suncoast had a good reputation and some dealings with Mike which put me at ease. Other wise I would of had to ship my broke truck to someone that knew what they where doing.

Why do you want a 6speed anyways? Really that extra gear isn’t anything special. Chevy1925 is about the only guy I’ve seen that did it that was very happy with it.


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The 6th gear makes sense! Less wear and tear on drive terrain at highway speeds. Lower rpm in overdrive. I could just be a moron but that sounds like a decent thing to have to me. I’m getting 20 plus mpg now what if I dropped 400 rpm? Yea I know it will take a million miles in fuel economy to pay for itself but i dont just look at fuel mileage also gotta look at the wear and tear in the long run! Let me ask you something....why did they not continue making 5 speeds in the later duramaxs? And why have they continued to put the 6 speed to this present day? That’s some things I look at more of a bigger picture than just right now.


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[Chevy1925]

The 6th gear makes sense! Less wear and tear on drive terrain at highway speeds. Lower rpm in overdrive. I could just be a moron but that sounds like a decent thing to have to me. I’m getting 20 plus mpg now what if I dropped 400 rpm? Yea I know it will take a million miles in fuel economy to pay for itself but i dont just look at fuel mileage also gotta look at the wear and tear in the long run! Let me ask you something....why did they not continue making 5 speeds in the later duramaxs? And why have they continued to put the 6 speed to this present day? That’s some things I look at more of a bigger picture than just right now.


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well, since you like to answer a question with a question, answer these by researching and you will know why.

How much power did the newer trucks make?
what was the MPG gain gm saw with this vs older models?
how easy is it to gain a 6th gear?
what internal mods do the 6 speeds have over 5 speeds?
how are the electronics different?
what emission standards did they gain in 2006?

im sure i can add more but that will paint the picture for you

 

[Dozerboy]

The 6th gear makes sense! Less wear and tear on drive terrain at highway speeds. Lower rpm in overdrive. I could just be a moron but that sounds like a decent thing to have to me. I’m getting 20 plus mpg now what if I dropped 400 rpm? Yea I know it will take a million miles in fuel economy to pay for itself but i dont just look at fuel mileage also gotta look at the wear and tear in the long run! Let me ask you something....why did they not continue making 5 speeds in the later duramaxs? And why have they continued to put the 6 speed to this present day? That’s some things I look at more of a bigger picture than just right now.


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If Chevy1925 didn’t paint enough of a picture for you I will add this. Somethings sound like great ideas and don’t turn out to be.

FIY a bunch full of of us have been Duramax Enthusiast for 10+ years. Wait enthusiasm is putting it to lightly. Some of these guys eat, breathe, and sleep Duramax. We are not stupid and we don’t give bad advice, but if you want to learn something the hard way it’s your dime. Since you obviously don’t want our advice, because several people have asked you what your plans are for the truck and you haven’t responded.


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[DAVe3283]

I have a Suncoast 6 speed kit in my Suburban, and I love it. The shift strategy is great on a stock motor with a ~200 HP tune. The more modified your motor/trubo setup is, the more you'll need custom shift points. The Duramax Tuner kit seems to be better in regards to working with the customer on shift strategy.

I don't think I get a mileage benefit from the 6 speed, but it does drop engine noise a bit on the highway. I like the conversion enough that I'm considering one for my truck, but it'll need a lot of shift strategy mods for that motor.

If you only have the money for one, build the transmission. A stout tune and a built transmission is a lot of fun to drive, and might net you more MPG gain than a 6 speed on a small tune. That's my 2¢, and I'm one of the people who likes the 6 speed conversion.

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[sam_rork]

I have a Suncoast 6 speed kit in my Suburban, and I love it. The shift strategy is great on a stock motor with a ~200 HP tune. The more modified your motor/trubo setup is, the more you'll need custom shift points. The Duramax Tuner kit seems to be better in regards to working with the customer on shift strategy.

I don't think I get a mileage benefit from the 6 speed, but it does drop engine noise a bit on the highway. I like the conversion enough that I'm considering one for my truck, but it'll need a lot of shift strategy mods for that motor.

If you only have the money for one, build the transmission. A stout tune and a built transmission is a lot of fun to drive, and might net you more MPG gain than a 6 speed on a small tune. That's my 2¢, and I'm one of the people who likes the 6 speed conversion.

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Ok thank you for your opinion all I’m really looking for is real opinions....good job


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[superswamper003]

Build the transmission. Considering your first post was that you wanted the trans to be able to handle your current modifications (which you have not yet posted what these mods are)

 

[sam_rork]

Build the transmission. Considering your first post was that you wanted the trans to be able to handle your current modifications (which you have not yet posted what these mods are)

No one asked.


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[sam_rork]

No one asked.


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Also maybe I’m paranoid but I guess i dont know how much my stock tranny will handle I do not want to completely destroy it want to preventative maintenance it before that happens. Someone told me if I ran my higher tunes with my bigger injectors it wouldn’t last long at all but transmissions are not what I know enough about so that’s why I came on here to ask questions.


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[Jacy_dzlguy]

Also maybe I’m paranoid but I guess i dont know how much my stock tranny will handle I do not want to completely destroy it want to preventative maintenance it before that happens. Someone told me if I ran my higher tunes with my bigger injectors it wouldn’t last long at all but transmissions are not what I know enough about so that’s why I came on here to ask questions.


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Like was said already, post current and/or planned future modifications so those trying to help know what you’re throwing at the transmission..

 

[Trimox]

Run it hard till it is stuck in 3rd gear and you will know what power it will hold. Search Search Search.

 

[torqued2dmax]

Lets think this over , if we take a transmission thats 13 to 18 years old that is designed to hold 250 rwhp and put 450 rwhp to it and add an extra top gear to the stressed transmission you may think it would be more likely to blow up than say a transmission package that is designed to take 600 to 800 rwhp , just a thought !

 

[sam_rork]

Run it hard till it is stuck in 3rd gear and you will know what power it will hold. Search Search Search.

Can you elaborate on that statement? Stuck in 3rd? I’m assuming that won’t have good outcome?


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[sam_rork]

Lets think this over , if we take a transmission thats 13 to 18 years old that is designed to hold 250 rwhp and put 450 rwhp to it and add an extra top gear to the stressed transmission you may think it would be more likely to blow up than say a transmission package that is designed to take 600 to 800 rwhp , just a thought !

Ok I’m not a complete idiot you don’t have to talk to me like I’m a child. And stock is 430 hp to the wheels i dont know how that converts to your 250 rwhp


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[torqued2dmax]

Can you elaborate on that statement? Stuck in 3rd? I’m assuming that won’t have good outcome?


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You would be correct to assume that !