Allison Trans

blankenshipgreg74

New member
Aug 27, 2022
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0
1
07.5 Duramax will not shift out of 1st. Haven’t been having problems, could filter be stopped up?? Electrical??


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blankenshipgreg74

New member
Aug 27, 2022
6
0
1
07.5 Duramax will not shift out of 1st. Haven’t been having any trouble. Filter stopped up? Electrical??


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2004LB7

Well-known member
Dec 15, 2010
4,237
500
113
Norcal
what are you reading the codes with? some wont read TCM codes so while it may have codes yours may not be picking them up
 

blankenshipgreg74

New member
Aug 27, 2022
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0
1
I let the parts store read it, you are correct, I’m sure their scanner will only show much.


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Dean E

Member
Mar 30, 2022
84
25
18
Blair, NE
Pull your tranny filter and look for metal. If that looks good then likely the TCM, they are known for frying. Not sure I would trust the scanner at the local parts store, what they have can vary greatly in function. Some are just a OBD 2 reader and might need more to read what the tranny is doing. There are plenty of Youtube videos talking about shifting issues from the TCM, there are a number of places that rework them. Dean