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Discussion Starter #1
Is there any way to easily identify the five speed vs six speed Allison? I'm looking to buy an LBZ and want the six speed. Anything in the VIN?
 

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Gone Fishin...
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LBZ's all had a 6 speed. Either automatic or manual.
 
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Discussion Starter #5 (Edited)
Glad to be here. Hopefully I can find a truck soon and add some content. I have a '71 Chevelle w/ LS1/T56 swap.

So were there any options for transmission on the auto side? Looking at a truck on Autotrader and it says 5 speed in the description, but has pictures of the Allison/Duramax badge.

So just to confirm. If it is a Duramax LBZ the only automatic option was the six speed Allison? I can verify the LBZ by the 8th VIN digit being a 'D'.

I've done quite a bit of research, but am slightly confused on this. Thanks for helping the noob out.

My Chevelle has a couple small pics in the latest Super Chevy if you get it, page 82/83 in the crack.


Pic to the left is my engine, they messed up the placement.
 

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Discussion Starter #6
Think I have it figured out. All 06-07 LBZ's came with the Allison and it was a six speed? Just want someone to verify.
 

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CRAZY CANUCK
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Verified, my truck is an 06 LBZ with the allison 1000 6-speed, all 06 trucks (including the very limited run of LLY's, yes there were lly's in 06) have the 6-speed :thumbsup
 

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You don't even need to open the door of the truck to tell if it's a 6 speed ally. Just look at the shifter. It has a fat handle and has + and - buttons on it then it's a 6 speed. The 5 speed handles are skinny and only have the button in the end.
 

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CRAZY CANUCK
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thats right, the shifter is... triangular in shape and the 5-speed is just rounded
 

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'Ol Builder guy
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Sort of on the same subject: What's the concensus on the 5 speed ally? besides not having the extra gear and the manual shift feature, is it still a tough trans or is it "softer" than the 6 speed?
 

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Gone Fishin...
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Sort of on the same subject: What's the concensus on the 5 speed ally? besides not having the extra gear and the manual shift feature, is it still a tough trans or is it "softer" than the 6 speed?
Having driven both I would say the 5 speed is more 'rough'. The shifts arent as smooth and it hold the gears longer. Also cruises at a higher RPM. I believe the tunes are different as well, which may account for the different feel.
 
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Gone Fishin...
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One more thing to add in regards to 'pump whine' on the transmissions. On the 5 speeds when the fluid is cold, everytime the vehicle is accelerated the trans 'roars'. The sound is the internal pump inside the Allison pushing the cold fluid. As the fluid warms the sound goes away. On the 6 speed the sound is greatly reduced. Part of it I beleive is the tune, but also the redesigned trans cooler lines help to warm the transmission up faster. Whatever the reason, the 6-speed is a lot quieter during cold weather operation.
 
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Sort of on the same subject: What's the concensus on the 5 speed ally? besides not having the extra gear and the manual shift feature, is it still a tough trans or is it "softer" than the 6 speed?
MikeL has said that the 6speed is tougher because it has updated parts inside. IMO, I think Allison saw what Suncoast, Transgo, Mike and ATS were doing, and incorporated many of those upgrades into the newer transmissions.

That said, I'll keep my Merchant 5-spd trans. ~100 drag passes, a few sled pulls, and 40,000 miles....no problems.
 
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