LB7: Transmission won't shift out of first gear

[[email protected]]

Was driving my 03 Duramax today, truck went into neutral by its self, service abs system came on, check engine light came on with codes P0700 and P0500, and speedometer quit working, truck will only move in first and reverse


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[WVRigrat05]

Has it had any Transfer case issues? Sounds like the transfer went out to me.

 

[[email protected]]

No no transfer case issues, it still goes in and out of 4 wheel drive


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[Evan@InglewoodTrans]

No no transfer case issues, it still goes in and out of 4 wheel drive


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If the speedo isn't working then the speed sensor in the T-case isn't reading. If it isn't it won't shift.

 

[WVRigrat05]

Sounds like the ring slid on the shaft.

Park the truck on level ground and put in neutral, and see how much the yoke moves up and down, check the oil, bet it's full of metal.

 

[[email protected]]

No movement on yoke


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[WVRigrat05]

Need to get a better code reader, those codes are generic codes. Could be a wiring issue or a bad speed sensor, but check oil for metal.