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I am curious as to everyones opinions why raising the line pressure in the Allison does not help to prolong the life of the clutch packs.


I am new to the Duramax, but have built countless numbers of 400+hp gas engines, and put them behind Turbo 350, 400 and other smaller transmissions with good success. Running these transmissions in their stock form was quick death, but even simple shift kits could make big improvements. We never needed to go full manual valve body, sprags, and clutches until well into the 500hp range.


I know the Duramax torque numbers are much greater, but why is there nothing offered between a stock Allison and a full on clutch replacement kit?
 

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Amric said:
I am curious as to everyones opinions why raising the line pressure in the Allison does not help to prolong the life of the clutch packs.


I am new to the Duramax, but have built countless numbers of 400+hp gas engines, and put them behind Turbo 350, 400 and other smaller transmissions with good success. Running these transmissions in their stock form was quick death, but even simple shift kits could make big improvements. We never needed to go full manual valve body, sprags, and clutches until well into the 500hp range.


I know the Duramax torque numbers are much greater, but why is there nothing offered between a stock Allison and a full on clutch replacement kit?
personally i think it may help to a degree if you raised the pressure on a new tranny before it caught any abuse,but if you add any real power it would be like trying to stop a juglar wound with duct tape....jess
 

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The current Allison 2001 - 2003 uses a fixed line pressure, there is no force motor to adjust line pressure with. If you raise line pressure within the transmission you will have it all the time which works the pump harder and causes failures. This is just some of the problems within the allison and our upgrade kit will solve them but there are patents applied for the modifications that we make. Automatic Transmission Specialties adds a force motor to the valve body and controls it externaly but this is very costly and will not work on the new '04 model transmissions as Allison has added a force motor to the unit that is computer controlled.
 

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thats a good question, but the allison is so much more advanced then the old hyromatics of days gone bye. You can put all the line pressure you want but if the trim solonoids dont let it flow, it aint doing any good. Becuase of the nature of the beast, there isnt really any in between with these tranny's like the other brands. The allison uses no bands, sprags, orifices, check balls, one ways, accumlators, nothing. Just five big clutch packs, three planetary sets and solonoids. thats it. Easy compared to those complicated hydromatics. I have spoke to allison engineers and its common consensus that unless you can make the Allison think different, your not gaining much. Of course, Suncoast and others manage to beef the tranny quite abit with out programming changes, that I know off..
 

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Diesel Tech said:
Automatic Transmission Specialties adds a force motor to the valve body and controls it externaly but this is very costly and will not work on the new '04 model transmissions as Allison has added a force motor to the unit that is computer controlled.

All '04s or just the ones that will come in January with the new Duramax? Do you have any plans on reprograming the '04 computer controlled force motor?
 

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Amric


ALL '04's have the new setup and Allison will be offering an upgrade kit for the older units. To install the new parts the TCM must be reprogrammed. Not sure if or when GM will bring it to market. We have already used our transmission upgrade kit in the new units and it works fine. We are currently working on the code for the 01 - 03 units and will look into the 04 code in the future.
 
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