Allison with no defueling

mike diesel

mike diesel

I'm alright.
Sep 6, 2012
4,005
0
36
SLC, Utah
I realize an allison needs defueling to live. And once people hit high enough horsepower seems the allison won't do what they want anymore as far as shifting fast enough.

Everyone says an allison will live a short life with no defuel and I'm not here to argue that fact. I'm simply wonder how long a fully built allison will actually live running behind say 400 horse all the way to 1000 horse. With no defuel, will the allison actually shift as fast as a built 47re?

What makes the 47/48re shift so dang fast? I've got a decent understanding of how/why an allison works but really don't know much about a "duraflite".

If money was no concern I would buy a few fully built to the hill allisons and see just how long one would last with zero defuel. But well, I'm not rich.
 
juddski88

juddski88

Freedom Diesel
Jul 1, 2008
4,655
119
63
Chesterfield, Mass.
mike diesel said:
I realize an allison needs defueling to live. And once people hit high enough horsepower seems the allison won't do what they want anymore as far as shifting fast enough.

Everyone says an allison will live a short life with no defuel and I'm not here to argue that fact. I'm simply wonder how long a fully built allison will actually live running behind say 400 horse all the way to 1000 horse. With no defuel, will the allison actually shift as fast as a built 47re?

What makes the 47/48re shift so dang fast? I've got a decent understanding of how/why an allison works but really don't know much about a "duraflite".

If money was no concern I would buy a few fully built to the hill allisons and see just how long one would last with zero defuel. But well, I'm not rich.
Click to expand...

There are guys who have figured out how to make the duramax/allison shift plenty fast at well over 1000 hp, or they've hired guys that know. Defuel is still there but you have to remember that a defuel is felt differently at 500hp than at 1000hp.
 
IOWA LLY

IOWA LLY

Yes, its really me
Feb 23, 2007
2,275
4
0
You can run without de-fuel. But its not as simple as turning it off and away you go. Ive spent a lot time developing tuning that works around no de-fuel. I have trucks with stock transmissions and 360rwhp, all the way up to over 1000RWHP and built transmissions running no de-fuel with great results.

But make no mistake, it took a LOT of time and experimenting to make it work correctly. And to run a built trans with no de-fuel requires everything to be just right inside the trans, and with the tune. But once you get the whole package to work together correctly it is incredible how well the Allison can shift.

If you wish to try it, be prepared to break stuff as you learn. And don't expect your trans builder to warranty stuff if you screw it up. :thumb:
 
DIESELMAFIAPER.LB7

DIESELMAFIAPER.LB7

<----new hotness
Jan 17, 2010
5,163
12
38
idaho
shop.dieselmafiaperformance.com
mike diesel said:
I realize an allison needs defueling to live. And once people hit high enough horsepower seems the allison won't do what they want anymore as far as shifting fast enough.

Everyone says an allison will live a short life with no defuel and I'm not here to argue that fact. I'm simply wonder how long a fully built allison will actually live running behind say 400 horse all the way to 1000 horse. With no defuel, will the allison actually shift as fast as a built 47re?

What makes the 47/48re shift so dang fast? I've got a decent understanding of how/why an allison works but really don't know much about a "duraflite".

If money was no concern I would buy a few fully built to the hill allisons and see just how long one would last with zero defuel. But well, I'm not rich.
Click to expand...

FWIW I ran no defuel on my trans for 50-60k miles no issues ran multiple 12 sec passes trans went 100k before it needed a refresh and the c2 c3 and c4s were burnt was all I loved the shifting with no defuel and you don't need a new tcm one table kills it
 

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DIESELMAFIAPER.LB7

DIESELMAFIAPER.LB7

<----new hotness
Jan 17, 2010
5,163
12
38
idaho
shop.dieselmafiaperformance.com
IOWA LLY said:
You can run without de-fuel. But its not as simple as turning it off and away you go. Ive spent a lot time developing tuning that works around no de-fuel. I have trucks with stock transmissions and 360rwhp, all the way up to over 1000RWHP and built transmissions running no de-fuel with great results.

But make no mistake, it took a LOT of time and experimenting to make it work correctly. And to run a built trans with no de-fuel requires everything to be just right inside the trans, and with the tune. But once you get the whole package to work together correctly it is incredible how well the Allison can shift.

If you wish to try it, be prepared to break stuff as you learn. And don't expect your trans builder to warranty stuff if you screw it up. :thumb:
Click to expand...

while agree on the risks I did it myself im by no means an expert my splines on the hub and gears and shafts looked perfect upon refresh after all the abuse I put it threw lol
 
Chevy1925

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,222
5,056
113
Phoenix Az
An allison will never be a 47/48 and a 47/48 will never be an allison. The internals of those two trans are completely different so they will never shift the same way
 
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