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Discussion Starter #1
I was reading on the chevrolet web site the other day and i noticed that the LLY duramax will not have as much power with the six speed transmission. I was wondering why this is. I drove my uncles 2001 d/max 6spd and was very impressed with the power. Just curious.
 

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It's not a problem with the tranny. The ZF is pretty stout. The problem lies with the clutch design. It can barely handle the LB7 power output levels without slipping.


Later...
 

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GM states that the 6sp will have 300HP/520TQ, which is the same as the LB7. Keep in mind that it is just a programming change. It can be remedied shortly.
 

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Discussion Starter #4
Do you know if they will change the clutch in 2005. I hope so. I wa interested in buying a Dmax, but would like to shift gears. Dont know why i just do.
 

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Todd


I hear ya. I wanted the 6sp too, since all trucks I'd ever owned were manual. That is, until I drove a truck with the Allison. It's unlike any automatic tranny I'd ever driven. (Trust me, it's NOTHING like the ford PowerStroke/Automatic combo).


As you can see by my tagline, I ended up with the Allison. I have no regrets, whatsoever.
 

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Discussion Starter #6
Is the power the same. Ive always heard that a manual transmission will out run out pull and out last an auto. Theres no doubt the allison is the best. It will always be, i just like a six speed.
 

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The tranny likely will, the clutch/flywheel is another story though.
 

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The manual will give most drivers better fuel economy, and a skilled driver with identical HP will out accelerate an automatic.


I race a 6-sp Corvette, and wouldn't want an auto racecar. But for towing, off-roading, and city driving, gimme a slushbox.
 

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In most cases I'd agree with you on the acceleration, but with a turbo diesel keep in mind that with an auto you stay at full boost between shifts. With a handshaker your boost drops to 0 and has to rebuild in every gear.
 

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Camstyn said:
In most cases I'd agree with you on the acceleration, but with a turbo diesel keep in mind that with an auto you stay at full boost between shifts. With a handshaker your boost drops to 0 and has to rebuild in every gear.

That is not true. Boost will not fall completely off if you shift quickly and since most programs defuel at least a little bit with the allison it could be a wash.
 

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Good point, I've never actually watched the pyro while I shift I just assumed it would drop to near 0.


I guess the only other disadvantage is being able to launch under boost with an auto. I can't think of any practical way to do this with a standard..
 

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McRat said:
GM states that the 6sp will have 300HP/520TQ, which is the same as the LB7. Keep in mind that it is just a programming change. It can be remedied shortly.

BS. . . .
. . . GM cannot remedy it. The clutch, hydraulic system, flexplate, and pressure plate are crap.



I have a hot juice and it is not stacked with anything, unlike some of the Allison users. I have yet to hear from ANYONE about a fix for the ZF6 clutch crap.


It should be easier to beef up, and cheaper also, than an Allison. But there are a ton of Allisons out there and not very many of the mannys. Ergo, no one seems to be working this problem . . .
 

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They don't know whats wrong with mine. I have over 9000 miles on my truck and I just had the 4th flywheel put in my truck. I don't want an automatic but its getting to the point where somethings got to be done. Because they are pushing my patience
 

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I debated on this issue before ordering also, but after reading posts about problems with the ZF, my decision was very easy. Who wants too spend that kind of money on a truck and have problems due too a poor design.
 

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FWIW a buddy of mine has a crewcab longbox 2500HD, dmax/6spd and it spends most of its time towing enclosed trailers.. He's got the 90hp Juice (4.61) and it's always on level 4, he's never had any problems with the clutch (yet).. He's got about 15k miles on it.


I've given mine a few runs with the Juice/Attitude on level 5 (125/325) and the clutch doesn't slip in 6th with the foot to the floor. I'm sure if I did it all the time it would eventually start to slip but they seem pretty stout in mine and my buddy's trucks.
 

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I had three replaced before I put juice to it. Thats the bad thing. I have found out that GM was wise enough to put a single mass flywheel in the 4500 and up. I would learn from there misstakes then we wouldn't be having this discusion. They had the same problems with the 6.5 but seems like they were stupid enough to try it again. If they would pay attention to Ford then they wouldn't have this problem. Fords got a single mass flywheel in there staight gears.
 

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My 6 never slipped but I had the lovely squeak. Friend has LLY 6 and he replaced the flywheel at 900 miles. Mine pulls good for now. Time will tell.
 

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Mine is going in tomorrow morn for a 'cool-man' trans cooler install (warranty). The rep seems to think this will solve the hard pedal issue.
He dosen't seem to understand the clutch slips because it is crap and can't be beefed up because the flexplate is crap, too. . . .
 

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Discussion Starter #19
I know the LLY has more power but does it come with a six speed or not. Im sorta confused because on the chevy website it says that with a six speed tranny it has the lb7 power. My uncle has a lb7 w/ a six speed and it is some kinda stout. He works for a rodeo company and he hauls a 30 ft steel trailer loaded w bucking bulls. All he has in it is a 45 hp chip. He has had no problems.
 

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The LLY is the only motor now, it just has the lb7 ratings for stick shift.





As for launching slide your foot off the clutch at about 2500 rpm, if everything holds together, it should make a mean launch



Do like the turbo rice burning bikes do and rev the motor to get boost up then drop rpms and launch.
 
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