Lbz tune

SSjohnson08

New member
Feb 13, 2020
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Alright guys I’ve run into an interesting issue, I forgot to save my factory ecm file when I first done the tuning on my truck. Ended up finding another file so I could have a spare to work with. I did however save my trans file but on the speedo parameter my trans has the final drive ratio as 4.10 and gear ration as 3.73, the file that I am using has the final drive as a 3.73. I guess what my question is do I need to change it to match my factory trans file before putting the new tunes on or should I read the trans one more time just to verify that what’s in it is correct? Noted: I haven’t done anything at all with the trans tuning and also in the pics the first table is the file I’m using for my new tunes and the second is my factory trans file. Any help would be appreciated.
 

2004LB7

Well-known member
Dec 15, 2010
3,954
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Norcal
Every Allison transmission file I've looked at had 4:10. Changing it could lead to some weird shifts and other undesirables as we don't have all the tables that refer to that 4:10 table and there is likely a lot of them.

Leave it at 4:10
 

collinsX

On a Time Out
Mar 30, 2017
20
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Every Allison transmission file I've looked at had 4:10. Changing it could lead to some weird shifts and other undesirables as we don't have all the tables that refer to that 4:10 table and there is likely a lot of them.

Leave it at 4:10
My buddy's uncle got this new LBZ project with weird shifting issues. I'll come over to his garage tomorrow right after I finished installing railings hard tonneau on the truck. We've been asked to check, the previous owner might have changed the trans ratio.
 
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THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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ZEPHYRHILLS, FL
I know somebody that changed it and his would go into grade braking on level ground when he touched the brakes and all kinds if stuff. Leave it alone, we don't have access to but maybe 1% of what's in there, so be VERY careful making changes.