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Discussion Starter #1
I just heard a rumor yesterday that our Allison 1000 trannies are actually 6-speeds with the 6th electronically locked out, any truth to this out there??
 

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I think that is partly true. The sixth gear is not "locked out", it's just not implimented. I think another solonoid and some other things have to be added as well as software. I heard also that the 2007 models will have the six speed. I hope so.
Edited by: Flyboy
 

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Well actually:


1. 1st TQ unlocked


2. 2nd TQ unlocked


3. 2nd TQ locked


4. 3rd TQ unlocked


5. 3rd TQ locked


6. 4th TQ unlocked


7. 4th TQ locked


8. 5th TQ unlocked


9. 5th TQ locked


Although it does not shift in that order, you have a 9 speed transmission. I do not believe the TQ ever locks in 1st, even it T/H mode.
 

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Not sure if there is currently the hardware in there, but I do know the 6speed allison is being developed now... I heard this from the Alli engineers...


I would hope that all stays the same with the gearing that we have now, but adds a super overdrive (0.7:1) for those highway trips. This would help fuel economy by getting the RPMs in the range when going 70-80mph. I like the current gearing in the tranny just fine right now.


BTW, Does anyone have what the tranny gearing is now? I can't find it anywhere...
 

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Discussion Starter #5
nassdmax said:
I would hope that all stays the same with the gearing that we have now, but adds a super overdrive (0.7:1) for those highway trips.




This is what I was hoping for too
 

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The current Allison 1000 gear ratios are...


First: 3.10
Second: 1.81
Third: 1.41
Fourth: 1.00
Fifth: 0.71
Reverse: 4.49


The story I remember hearing over at the "page" a while ago was that by activating the 6th gear, you would be getting a "super" overdrive...with a 0.61 ratio. This would be great for driving 75 to 80 mph and still keeping those RPMs down around 2K for better mileage.
 

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It would be interesting to see the results if one were to change the rear end to 3.42 from 3.73. I wonder if fuel mileage would increase much? There is plenty of low end power there and with a 3.10 first gear I doubt you would have any problems.


A 6 speed with an ultra overdrive would be the ultimate solution! Edited by: Max Power
 

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your pms are full max
 

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I still like the low grunt to get a big load moving with the current setup. Super overdrive would be awesome as this is my daily driver too... I put 600-700+ miles a week on, and 500 of them are highway to work and back.


Fully loaded for me is something like 26K combined weight... (truck, gear, gooseneck 10 ton trailer, Case 580L backhoe) Sometimes I need all I can get to get the backhoe out of some peoples driveways and launched from some stoplights that are on an incline.


You have to remember that with that load, there is no high speed driving for me, just backhoe delivery on side roads. 65mph max. Also to keep the cops off my tail!
 

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Aren’t' the 1000s supposed to be basically the same case as the 2x00 series? I've been told you could just swap in the stronger version (if you could work out the electronic issues) to get much higher torque capacity as well as 6 speeds with very little effort. I'm not claiming to know anything about this, or planning to do it, but it seemed it might be relative to this thread, and I'm curious...
 

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I remember I was at the allison dealer and asked the tech if you could swap a 2000 that has the 6 speeds. He said they could do it, but you would need GM to sign off on it before they would even attempt it. It would be nice for those long trips at 75-80 mph when the current set up is at almost 2500rpms.


LA DMAX
 

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I believe my neighbor's motorhome has a 6 speed Allison mated to a Cat diesel. It's in a Freightliner chassis.
 

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LA DMAX said:
I remember I was at the allison dealer and asked the tech if you could swap a 2000 that has the 6 speeds. He said they could do it, but you would need GM to sign off on it before they would even attempt it. It would be nice for those long trips at 75-80 mph when the current set up is at almost 2500rpms.


LA DMAX

If all you are after is to lower the rpm in overdrive at highway speeds, just change out the tires to 285`s or 295`s. I run 285/75/16 and the truck cruises at 2000 rpm driving right at 75-76 mph.
 

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nassdmax said:
Not sure if there is currently the hardware in there, but I do know the 6speed allison is being developed now... I heard this from the Alli engineers...


I would hope that all stays the same with the gearing that we have now, but adds a super overdrive (0.7:1) for those highway trips. This would help fuel economy by getting the RPMs in the range when going 70-80mph. I like the current gearing in the tranny just fine right now.


BTW, Does anyone have what the tranny gearing is now? I can't find it anywhere...

The Allison already has .71 overdrive gearing so going to .70 will not help enough to make it worh anything.


Ask Eric about the 6th gear, Seems like he mentioned something about more power again for 05 and also the 6th gear.
 

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allison has 3 sets of planatary gears, that gives it a possible 6 forward gears. Its in there, just needs to be used. Look for it in a few years



Dont think its really feasable in an 'aftermarket' sense to activate it as its hydraulically and electrically not there at this time
 
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