New rebuild p0756 stuck in 2nd gear

Jan 28, 2014
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So I just finished rebuilding my trans 07 lbz duramax 6speed. I replaced c1-c4 clutch packs with gpz clutch packs c5 look fine so I didn't replace it. I did the heavier regulator spring and a lock up boost valve and a transgo Jr and new transgo shift valves. Its throwing a p0756 in park I can clear it and it comes right back its stuck in 2nd gear I pulled the valve body checked everything meticulously valves are free solenoids check out good manifold switch checks good I'm at my whitts end with this thing any help would be great!
 
Jan 28, 2014
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Ya I guess that's not considered a rebuild...however I was very careful and i thought I had everything right and I'd would appreciate any help I can get on this thanks!
 

gtmax

New member
Apr 9, 2008
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0
Were your original Allison shift valves bad? When I run into a problem usually in a valve body that someone previously butchered, if it needs a new valve I go with a new original Allison valve.
 
Jan 28, 2014
33
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Were your original Allison shift valves bad? When I run into a problem usually in a valve body that someone previously butchered, if it needs a new valve I go with a new original Allison valve.

no i had a problem with them sticking earlier and so i ordered the trans go ones but in the mean time i took it apart and cleaned the valve slots and that took care of it i just figured i throw the new ones in while i had it apart again
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
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Fullerton CA
Were your original Allison shift valves bad? When I run into a problem usually in a valve body that someone previously butchered, if it needs a new valve I go with a new original Allison valve.

That's cause you're smart George.:D:hug:
 
Jan 28, 2014
33
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no i had a problem with them sticking earlier and so i ordered the trans go ones but in the mean time i took it apart and cleaned the valve slots and that took care of it i just figured i throw the new ones in while i had it apart again

Sorry if this post was confusing the truck is NOT fixed yet
 
Jan 28, 2014
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Thanks guys for the help put the stock valves back in and made sure they were free and it worked fine till I got warmed up and then it threw a p0762 and went into limp mode didn't have time to mess with it last night but I drove it this morning and it never messed up so I'll see how it goes but if I can get the e valve to quit sticking I think I'll be good to go!

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