5 speed to 6 speed conversion.
- Thread starter Bustedknuckles
- Start date
If the TCM is unlocked, I'll buy in in a second for my GMC, and possibly chuck the Suncoast 6-speed conversion TCM in the Suburban for this as well. The Suburban is a stock (hard parts wise) LB7, so the Suncoast 6 speed kit is great, but I can't run a locked TCM on my built motor. I'm changing things too often that require remapping the shifts to keep street manners.
But I am guessing it is locked, like the rest. I understand why they do it, but I don't have to like it.
But I am guessing it is locked, like the rest. I understand why they do it, but I don't have to like it.
And that’s the conclusion I always come to :thumb: thanks for the honest reply Evan
If someone is really worried about mpg they should sell their truck and get a Prius
Well, the same thing can be said about trying to run 9s and faster in an Allison. At the end of the day, it's still an Allison; a transmission that was never designed for any kind of racing and provides no benefits at all trying to use it in the field either. It's ancient tech. If someone was trying to build a full tilt race vehicle, an Allison is on the bottom list of recommendations as well. It's not for everyone, but there are still people out there trying to use it. No difference here. Because when you weigh the overall cost of trying to use an Allison to run 8s and faster vs better options out there, the cost effectiveness is just not there either.
But we do it anyways.
If everyone was honest and trust worthy it wouldn't have to be locked. But unfortunately this is not the case.
For the avg guy this would be great if the price is right. The 5 speed was my biggest complaint with the LLY. On a back road at 55 I was right around 1700-1800 rpm and all was nice and quite. Get on the interstate running 75 and rpm would be around 2200-2300 and a little loud. It was not the end of the world, just a little annoying.
I would pay in the $300-500 range to have gotten a six speed but that's about it.
I would pay in the $300-500 range to have gotten a six speed but that's about it.
Well, the same thing can be said about trying to run 9s and faster in an Allison. At the end of the day, it's still an Allison; a transmission that was never designed for any kind of racing and provides no benefits at all trying to use it in the field either. It's ancient tech. If someone was trying to build a full tilt race vehicle, an Allison is on the bottom list of recommendations as well. It's not for everyone, but there are still people out there trying to use it. No difference here. Because when you weigh the overall cost of trying to use an Allison to run 8s and faster vs better options out there, the cost effectiveness is just not there either.
But we do it anyways.
I figured you'd have an ornery post and I understand you taking offense because of your time invested and it being your project and I agree on the Allison not being a race transmission because well...it's not. Unfortunately what I said is true and no way of going about is going to increase its effectiveness. But some people will still want just to have it as with many other modifications. I build competition transmissions on the regular and I get not even a handful of 6 speed conversion request a year so that says all I need to know. Unfortunately not to many people want a $20,000+ TH400 swap and 47/48 are far from the best option. This just my opinion from what I've seen and I apologize if you're taking it personal that's not my intention. It's great to have incredibly smart people like yourself in the industry who are able to come up with ideas and actually apply them.
well thats about half the cost a new 6 speed or 5 speed valve body lol.
i dont think you are getting one
you cant hardly get parts for that price. Imo its more worth the swap if you do a lot of traveling with small or no trailers. Which is what the guy that came up with it does.
I think it’s also probably a market that is heavily influenced by the state. In Iowa a 6 speed is completely unnecessary in my opinion. However when I travel to Texas and the speed limit is 75 and if your going 80 your getting passed then I could see the appeal.
However, what most people don’t understand, or don’t want to admit is that the Duramax is happy to cruise along at 2500 rpm. It’s not happy or really designed to cruise along at low low rpms making big torque.
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However, what most people don’t understand, or don’t want to admit is that the Duramax is happy to cruise along at 2500 rpm. It’s not happy or really designed to cruise along at low low rpms making big torque.
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There's nothing about it to take personal. This isn't a thread about personal feelings towards things.
This whole thing isn't much of a time consuming project as much as it's just a by-product of other development that is on the table. I figured some would find it useful and most would still retain the same views. Having heard the reviews of all the other conversions and knowing where all their IP had come from, I figured at minimum to provide something that was done from scratch, not stolen and in the end actually works.
The bigger picture to this is the ability to learn and understand the fundamental controls of the Allison calibrations and learn how to further control the software to do what we want and need to accomplish greater things with it down the road. IE... get that 7 second pass on an Allison, retain and control defuel properly and support further development and adaptation of the platform to other areas.
This is just to be a better thing for the people that are interested in this area of the Allison.
And because I was bored. :roflmao:
Oh I hear ya. When I swapped to 4.56 gears from 3.73 on my 37’s, anything over 70mph drops mpg significantly even with tuning changes. Even at 70 I’m still 2mpg lower than I was on stock gears. It’s basically like my truck is on 245/75r16 tires (what it came factory with). I look forward to the lower engine speed (quieter), bring mpg up some, and cruise faster than 70mph loaded or unloaded without spinning the heck out of the engine the whole way.
That’s the other thing, my pilot injection shuts off above 2500rpm which means when I’m going over 80, my wife knows (which leads to “slow down!”) and things get a little louder inside lol. 85-90mph sounds like I’m ready to race anyone next to me lmao
The pilots easy to take care of. Contour your cutoff table instead of a flat rpm cutoff. I cut pilot at 2300 in the upper fueling because I've found the turbo lights quicker without it, but in the cruise fuel areas I keep it till 2800 because sometimes pilot would kick out under half throttleor so, and I just didn't like the noise. Took a little time, but you never notice my pilot going out. And since you now have an lly, you can stagger when pilot goes out to furthur refine it.
As to a 6 speed swap, it would be nice, but I don't drive enough hwy to justify it anymore with my failing health. When I did my swap, the conversion's were still very new, since I was regearing anyways, I just opted for 3.42 gears. It gives me the same final drive on 5th as 6th does with 3,73's. And it helps me to drive the limit because at 70 I have zero drone, on stock injectors I was good till 75, but the 45 sacs start to drone at exactly 70.5, so I know when I'm doing 70 dead on now.
Like Iwoa said I think a lot of it will be state influenced
Here in Florida if your not going 10 over your just a danger to everyone else trying to pass you
South Florida is even worse down there people do 85-90 on the highways and that’s the norm... well when it’s not gridlocked :roflmao:
Here in Florida if your not going 10 over your just a danger to everyone else trying to pass you
South Florida is even worse down there people do 85-90 on the highways and that’s the norm... well when it’s not gridlocked :roflmao:
Guys in west TX will like it, but the speedo still stops at 120... lol
I’m interested to see what other projects are in the works.
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I’m interested to see what other projects are in the works.
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yeah steve has gone over it with me. i may dick with it when i do the swap. all this truck sees is highway and mainly loaded. im also going to start looking into doing a full exhaust now. current exhaust dumps under the back of the cab and i want to take the drone out from there. Granted there isnt much with the second turbo and a muffler but after being in my dads 15.5 lml, i was spoiled....
I'd be happy if I could get consistent lockup at wot again. My swap will not shift right exvept with the infamous 01 TCM OS, and that's the ONLY OS that doesn't have the lockup table in it. I had it locking up good with stock injectors, but the 45 over sacs changed things a bit. Now it's a roll of the dice, like dealing with my wife.
