Allison power handling capabilties in a lighter vehicle?

DieselS10

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May 12, 2009
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I posted up many many months ago wondering if a 4L80e would handle much from a Duramax, but as luck would have it I ended up getting one with the Allison. :thumb:

So, I was wondering if the 5 speed 2005 Allison behind my LLY is capable of being subjected to more power due to a slightly lower vehicle weight? I will be getting EFI Live for tuning and the tranny will remain stock until sometime in the not to distant future. My truck weighed 5,760lbs with the 6.5/4L80e and after hearing from THEFERMENTANOR I am expecting it to come in right around 6,000 with the addition of the LLY/Allison, is this enough of a weight difference from the factory equipped Duramax trucks to give the tranny any advantage in the form of being able to safely add any more power than the 90hp over stock safe zone that I keep reading about?
 

Mike L.

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"05 is the weakest Alli out there. You will not hold much power with it no matter what weight. Too many things wrong with it.
 

Chevy1925

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anything over stock tuning is shortening the life of the stock ally. there is no way to say for sure it will last longer on a higher tune before it limps untill it limps 9or you tear it down and look at the clutches periodicly), and at that point its too late. Personally, i wouldnt go over a 50hp tune, if you want more, build the trans while its out of the truck now and save yourself the headache down the road. Your not gaining hardly any longevity being at 6k with any tuning higher than stock.
 

DieselS10

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"05 is the weakest Alli out there. You will not hold much power with it no matter what weight. Too many things wrong with it.

Well that isn't what I was wanting to here, lol.

Thanks for the quick responses guys, I'll just leave it stock until I can build the tranny up, time to start shopping!
 

DieselS10

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Mike, what would you recommend doing to it. It will see occasional towing of not more than 12,000lbs and a max power level of whatever EFI Live is capable of with the stock components. I have no intention of upgrading the turbo, injectors, adding a CP3 or anything like that, it will be plenty for this truck with tuning only. Thanks in advance.

I tried to look on your website, but it isn't working at the moment.
 

THEFERMANATOR

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The GMT-800 trucks are actually pretty light due to GM's use of some aluminum and strategic planning of where to put beef and where not to. At 6000 pounds your weighing in pretty close to a standard cab long bed 4X4, so not really any weight savings there over the full size truck. If moneys tight I would call Mike and see if he will tell you how to remove the pressure knockdown from the trans and install the full transgo shift kit and one of his single disc converters. It won't be a built trans really, but should get you a good deal more holding power for not much money.
 

MaxPF

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Jan 12, 2011
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It will see occasional towing of not more than 12,000lbs

12,000lbs in an S-10? :rofl:

Listen Chief, just because you have 1 ton axles under there does NOT mean you have a 1 ton truck :rolleyes:

Also, doubled 241's behind a DMax is questionable at best. Heck, doubled 241's in anything is questionable...
 

duratothemax

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Aug 28, 2006
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12,000lbs in an S-10? :rofl:

Listen Chief, just because you have 1 ton axles under there does NOT mean you have a 1 ton truck :rolleyes:

Also, doubled 241's behind a DMax is questionable at best. Heck, doubled 241's in anything is questionable...

205's arent known to hold up behind duramax's either. And that cummins you have planned isnt gonna be any easier on it.
 

MaxPF

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205's arent known to hold up behind duramax's either. And that cummins you have planned isnt gonna be any easier on it.

I never mentioned a 205, but keep in mind the 205s you see blown up are in pulling trucks with a LOT of HP and torque. Not to mention they are universally Ford (driver drop) 205s, which are known to have a significant weak area around the PTO opening. They either break the output shaft or the case in that area. By his own admission he isn't planning on making that kind of power. Anyways, I said DOUBLED 241s are a bad idea. If you look at his sig he is planning on running a 241 range box mated to a 241 transfer case. That is a total low range reduction of 7.40 just in the transfer case. Add the Ally's 3.10 first gear and you have 22.94:1. If you figure 2x multiplication in the torque converter you have a potential torque multiplication of about 46:1. He won't even need 1/2 throttle to spit parts out with that kind of reduction.

FWIW, I am seriously reconsidering the 203-205 setup. For one thing, at 240lbs it is a LOT of weight hanging off of a fragile Ally tailhousing. Even with added support braces and 2 crossmembers its a worry. Second, it will leave me with a very short driveshaft. Finally, all those meshed gears in an oil bath soak up a fair bit of power and reduce mileage. Modern chain drive cases are relatively light and don't have as much loss. I can't use a 26x or a 27x since I have a passenger drop axle, but I have a perfectly good 241 with a slip yoke eliminator:

installed.jpg


I'm actually running that case right now behind the Cummins and 465. It uses the same planetary set as the 26x and 27x. The chain is narrower but can be upgraded to 1.5" using 241DHD parts. It has a massive support strut on the front drive extension to prevent case breakage. It's only weakness compared to the 26x and 27x is output shaft diameter, but since I'm never going to make ridiculous amounts of power or tow more than 6k lbs I doubt I will ever break it.

I've wheeled the piss out of this case with 37's for the last 4 years, and it still has the stock 1.25" chain. Believe me, I don't think aluminum (or magnesium) chain drive cases are weak by any means as long as they are properly supported. But, cascading one range portion in front of another is a bit excessive, and especially behind a DMax with big tires I don't think the rear case will live...
 

DieselS10

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That's a heavy S10 lol, my ext. cab shortbox 03 duramax weighs 5850lbs

Yes it is, it actually exceeds it's GVWR by a descent amount when it's empty, lol.

The GMT-800 trucks are actually pretty light due to GM's use of some aluminum and strategic planning of where to put beef and where not to. At 6000 pounds your weighing in pretty close to a standard cab long bed 4X4, so not really any weight savings there over the full size truck. If moneys tight I would call Mike and see if he will tell you how to remove the pressure knockdown from the trans and install the full transgo shift kit and one of his single disc converters. It won't be a built trans really, but should get you a good deal more holding power for not much money.

Thanks Ferm, I'll check into that, I really don't have the cash to drop into it right now, I'm due to have surgery next month and will be down for a couple of months.

12,000lbs in an S-10? :rofl: Behind, as in on a trailer...
Listen Chief, just because you have 1 ton axles under there does NOT mean you have a 1 ton truck :rolleyes:

Also, doubled 241's behind a DMax is questionable at best. Heck, doubled 241's in anything is questionable...

Thanks for the advice, but it really wouldn't make much sense to throw 1 ton's and a Duramax into something that couldn't possibly handle it without upgrading everything to handle the extra stress. You are more than welcome to come look it over, but I assure you that the rest of it, especially the frame, is completely up to the task. I would feel confident putting the frame in this truck up against any factory built 3/4 ton unit. FWIW it has already seen loads over 12,000lbs and handled it flawlessly. The wheelbase was stretched to 132.5" and the frame has been boxed, trussed and gusseted and recieved numerous extra cross-members to handle the torque, it is extremely rigid.

DSC02636.jpg


The only thing in the entire setup that could be in question is the second 241, if it fails it will recieve a 271, but not before then. I had already built the 241/241 setup and ran it behind the 6.5/4L80 that was removed for the Duramax and the driveshafts were already built for this setup, so there is no reason not to see how they hold up. As I understand it is possible to limit power with EFI Live for when it's in double low range, so that will help as well.
 

Mike L.

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12,000lbs in an S-10? :rofl:

Listen Chief, just because you have 1 ton axles under there does NOT mean you have a 1 ton truck :rolleyes:

Also, doubled 241's behind a DMax is questionable at best. Heck, doubled 241's in anything is questionable...

Sure glad you never called me Chief. We would have a Big problem. Don't like the way the name is used and hate dicks that use it.
Try and be nice richard.:thumb::D
 

whitetrash21

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"05 is the weakest Alli out there. You will not hold much power with it no matter what weight. Too many things wrong with it.

For my own personal edification, and cuz I drive an 05, what is different in the allisons vs other 5 speed allis? Is it fixable?
 

THEFERMANATOR

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For my own personal edification, and cuz I drive an 05, what is different in the allisons vs other 5 speed allis? Is it fixable?

It probably has more to do with the fact that 05 was beginning to push the limits of the 5 speed ALLISON in stock form, add in a tune and you can easily exceed it's limits..
 

Chevy1925

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For my own personal edification, and cuz I drive an 05, what is different in the allisons vs other 5 speed allis? Is it fixable?

Wes, you are screwed basically. they have a timed limit and counter in the TCM that counts how many times you hit WOT when tuned and for how long, after that amount of time or count (which ever occurs first) the trans blows up and makes a nice little mess all over the road. it then informs Onstar of the blow up and they call hazmat and PD for you. When hazmat and PD recieve the call from onstar, they are instructed per a police specific code to give you a huge fine/ticket/ and to pay for the hazmat clean up. Your truck is impounded for 90 days and can only be pulled out and dropped off by the impound company in which you pay all fees/tows. once back in your posession, you title is branded as "retard owner" and your insurance and registration fees are dramaticlly increased. EFI Live cant change that counter or time, only a very few select trans builders can change this and its only if they feel like it. Ask steve about this, its happened to him. this is why the 05s are so undesirable and cost you more than you know :rofl::rofl:.

sorry buddy, just had to give ya some crap :D :hug:
 

whitetrash21

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Wes, you are screwed basically. they have a timed limit and counter in the TCM that counts how many times you hit WOT when tuned and for how long, after that amount of time or count (which ever occurs first) the trans blows up and makes a nice little mess all over the road. it then informs Onstar of the blow up and they call hazmat and PD for you. When hazmat and PD recieve the call from onstar, they are instructed per a police specific code to give you a huge fine/ticket/ and to pay for the hazmat clean up. Your truck is impounded for 90 days and can only be pulled out and dropped off by the impound company in which you pay all fees/tows. once back in your posession, you title is branded as "retard owner" and your insurance and registration fees are dramaticlly increased. EFI Live cant change that counter or time, only a very few select trans builders can change this and its only if they feel like it. Ask steve about this, its happened to him. this is why the 05s are so undesirable and cost you more than you know :rofl::rofl:.

sorry buddy, just had to give ya some crap :D :hug:

Goddamn!! :den: .....on that note, anyone wanna buy an 05? :D