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Discussion Starter #1
Ok I work at a dealership.. This guy comes in today claims to be getting 24 mpg.. not overly believable but ok.. he also claims to be running the superchips 150hp chip... I didn't think these trannies were taking that kind of power.

If they are.. I sorely discounted them. This was on an 04 duramax. Not sure if it is a lly or lb7. Anyway I just thought it wouldn't take the same power put to the alli... he also claimed that at 70-75 he was running 2500rpms and getting 24?? come on anyone else buy this??
 

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Running a 450 RWHP tune I see about 16MPG Around town and a best of 20.1 on mostly all highway travel. All MPG's are hand calculated as i have no dic.

Oh yeah, these trannies are tough, Im honestly supprised mine is still in one peice!
 

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Moss got over 24mpg in the Diesel Power Challenge.I've gotten as high as 20-22 on summer fuel.I don't think it will be that high next summer with the ULSD fuel.

ZF's are tough!The stock DMF isn't.
 

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This tread has a common misconception going - the transmission, the ZF 6 speed, is very tough, its the clutch that is the problem. It is important to distinguish between the two components!
 

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These tranny's are real hard to beat. The only thing i've been able to brake is an out-put shaft. I done this doing a 4wd launch on black-top. A buddy of mine has the same kind of truck as me, same programmer, but an allison. He hasn't broke anything doing launches but he has put over $4k in the ally and my zf is stock except for clutch.
 

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Im putting down over 525 Hp, and have had no problems after i replaced the clutch. I get as much as 23 MPG hand calculated if i baby it, most of the time its around 18-20.
 

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Discussion Starter #7
Well.. sounds like I read some stuff misleading. I was under the presumption that it couldn't handle the raw power the alli could... even though it takes a bit to get the alli to hold it. 525 on stock trans is awesome.. especially when you figure in clutches are all you are replacing. How much are clutches? I may have to try to find one.
also can you get one loaded down with leather and all the trimmings?
 

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Cluches are as much as about 2K for a dual disc feramic puller clutch. Mine is a dual disc ceramic South bend solid hub and was about 1600.
 

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I have got 24mpg (hand calc.) in the summer, with mostly all hwy miles, and very little city; over 700 miles on those tanks. So 24 is possible, it seems the ZF trucks do get a little better economy than the Allison trucks. Stock for stock the ZF trans is stronger than an Allison, but a built Allison vs. a ZF?
 

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I have gotten 20-22mpg with every tank of fuel so far, minus the times I was towing. Hand calculated.
 

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I get 18 to 22 in the summer, but all depends on how I am driving
 

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Discussion Starter #12
BattleMax;1605210; said:
I have got 24mpg (hand calc.) in the summer, with mostly all hwy miles, and very little city; over 700 miles on those tanks. So 24 is possible, it seems the ZF trucks do get a little better economy than the Allison trucks. Stock for stock the ZF trans is stronger than an Allison, but a built Allison vs. a ZF?
How much are clutches? And has anyone had leather with their zf? I prefer manual any day of the week.. but when it comes to comfort I need my leather. :)
 
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