Allison tranny probs

[lb7_dmaxx]

I have an 01 duramax and the trans won't go in reverse and takes off in high gear I replaced the neutral safety switch but does the same thing and now the reverse light flashes I need help


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[greendury]

Codes?

 

[lb7_dmaxx]

I will have to hook the scanner back up to it I was so frustrated after I put the nsbs on I quit fooling with it


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[Mike L.]

Use a professional scanner and not a code reader to get codes when diagnosing.

 

[WolfLMM]

Been getting a lot of drive bys lately. No proper diagnosing just throw parts at it.

 

[hotdogstand]

I haven't been under the truck in a while, so I'm not certain of the particulars of this vehicle, but on many vehicles there is a small amount of adjustment in the switch mounting. Make sure that when the indicator says R that the trans selector lever really is engaged in that position instead of hitting between gears. Every now and then my truck won't register P even though the pawl has caught. I haven't touched the switch in years, but I had it off once because the display wouldn't say any gear at all and some warning popped up. Turned out moisture was getting into it.

 

[THEFERMANATOR]

And if you don't deburr the shift shaft when you replace the NSBU, you just ruined your new NSBU switch.