Allison 6sp: LML clutch clearances

BigDMax05

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Feb 2, 2009
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Looking for some literature or a professional's opinion on the factory specs for the clutch clearances in the newer LML 6 speeds. I've scoured the web looking and on here and I can't find anything. Any guidance will be appreciated. Thanks in advance.
 

PureHybrid

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Feb 15, 2012
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.005-.006" per friction face.

* I don't claim to be a professional, but I've had good luck shooting for that range*
 

Mike L.

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Looking for some literature or a professional's opinion on the factory specs for the clutch clearances in the newer LML 6 speeds. I've scoured the web looking and on here and I can't find anything. Any guidance will be appreciated. Thanks in advance.

First of all what are you doing? If you are doing after market clutches, stock specs are wrong. The above info is wrong.
With after market clutches, you better know the compression rate as what the clearance will be after a few thousand miles. Putting your own clutch kit together without knowing this info is stupid. Be carefull.
 

BigDMax05

Peanut butter and ladies!
Feb 2, 2009
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Indiana
First of all what are you doing? If you are doing after market clutches, stock specs are wrong. The above info is wrong.
With after market clutches, you better know the compression rate as what the clearance will be after a few thousand miles. Putting your own clutch kit together without knowing this info is stupid. Be carefull.

Mike I was hoping you'd chime in. I am using stock replacement clutches. No modified aftermarket clutches. Not putting together my own clutch kit just a stock rebuild. Truck was deleted and tuned and lived a rough life.
 

Mike L.

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If you are using stock frictions and steels ( LML is different than earlier models ), they only come in one size so it should be a no brainer. C3/C4 use waved friction plates for better oil retension. C3/C4 steel plates have a radius at 3 points for better clearance for the return springs.
 

BigDMax05

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Feb 2, 2009
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If you are using stock frictions and steels ( LML is different than earlier models ), they only come in one size so it should be a no brainer. C3/C4 use waved friction plates for better oil retension. C3/C4 steel plates have a radius at 3 points for better clearance for the return springs.

I have borg warner c3/c4 frictions. The frictions I have do not have any wave to any of them. C3 clearance I'm getting is .093" and c4 is .110".
 

Mike L.

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I have borg warner c3/c4 frictions. The frictions I have do not have any wave to any of them. C3 clearance I'm getting is .093" and c4 is .110".

OE clutches are Borg Warner. The early clutches are thicker except for C2. Using early clutches in an LML will throw everything off as far as clearance. You will never get 4 clutches in C3 using early clutches as the top plate is too thick. I hope you know what you're doing here mixing this stuff up.
 

BigDMax05

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Feb 2, 2009
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Way to loose. Even with a stock trans somwhere in the .060 area and you'd be good to go.

That's what my intuition lead me to believe but I'm being told otherwise by one of the techs at the company that sent me this kit. Defeo mfg. is the company and the tech told me he regularly sets the c3's between .90-.110". Thanks for the help!

OE clutches are Borg Warner. The early clutches are thicker except for C2. Using early clutches in an LML will throw everything off as far as clearance. You will never get 4 clutches in C3 using early clutches as the top plate is too thick. I hope you know what you're doing here mixing this stuff up.

Mike the clutches I have before me are very thin compared to older stock clutches I've seen/removed. I have 4 frictions in the c3 with what I have at the .093" clearance and 6 clutches in the c4 at the .110" clearance. I should note that I also had to get a new gm c3 top plate as the old one was trashed. This transmission is out of a 2015 Chevy 2500. Thanks for your input mike it does not go unappreciated!

Happy Thanksgiving to you both!
 

Mike L.

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The new clutches will compress after a few thousand miles and that clearance you have now will grow. I am very curious why your clutches are not waved. I have never seen B/W C3/C4 LML clutches that weren't. What color are the clutches?
 

BigDMax05

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Feb 2, 2009
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Indiana
The new clutches will compress after a few thousand miles and that clearance you have now will grow. I am very curious why your clutches are not waved. I have never seen B/W C3/C4 LML clutches that weren't. What color are the clutches?

They are greenish steel and blackish dark gray friction material. I tried uploading a photo but it won't let me for some reason. The frictions measure out to around .075" thickness and the steels are around .100".
 

Mike L.

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They are greenish steel and blackish dark gray friction material. I tried uploading a photo but it won't let me for some reason. The frictions measure out to around .075" thickness and the steels are around .100".

Rebestos clutches, not B/W. They will compress. You are way too loose.