Help with Service Engine Soon light!!
#31
I had a 2001 2500HD with an 8.1 and Allison 5speed.
I had the the same light come on once and the tranny was acting wierd. Delayed going into gear, reved then kicked hard into gear, would not switch gears, etc. Turned the truck off and trans was back to normal, but the service engine soon light was on. It ended up being the Nuetral Safety/Back up switch module. My dealer said that it was a common part to fail.
I had the the same light come on once and the tranny was acting wierd. Delayed going into gear, reved then kicked hard into gear, would not switch gears, etc. Turned the truck off and trans was back to normal, but the service engine soon light was on. It ended up being the Nuetral Safety/Back up switch module. My dealer said that it was a common part to fail.
How is the neutral switch replaced? Where exactly is it located and where does it go?
#33
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From what I've seen, those Allisons are like black magic, not many who really know the deal other than Diesel Tuners, GM/ Allison really locked them down, you may need to take it to a reputable dealer or GM diesel specialist, but, behind the 8.1, should be minimal issues, it takes a lot of torque to damage them but the electronics can drive you crazy at times, find a diesel/ allison specialist and have them take a look if you don't have a good dealer near you... Sorry i'm not more help, haven't owned one myself... Yet...
#34
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fixx
From what I've seen, those Allisons are like black magic, not many who really know the deal other than Diesel Tuners, GM/ Allison really locked them down, you may need to take it to a reputable dealer or GM diesel specialist, but, behind the 8.1, should be minimal issues, it takes a lot of torque to damage them but the electronics can drive you crazy at times, find a diesel/ allison specialist and have them take a look if you don't have a good dealer near you... Sorry i'm not more help, haven't owned one myself... Yet...
#35
Charter Member # 55
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I drove it to the auto parts store the day it threw the code and it drove fine. The store was only like 2 miles away but the truck drove fine without any hard shifting or anything.
How is the neutral switch replaced? Where exactly is it located and where does it go?
How is the neutral switch replaced? Where exactly is it located and where does it go?
#36
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The park/neutral switch is mounted on the drivers side of the trans. The new updated switch comes with a heat shield to protect it from the exhaust. The old switches would melt the resin inside and seep through to the wire pigtail and glue them together often causing the plug and harness end to be replaced together. The dealer sells a replacement pigtail but they do not give it away, its more than the switch if I remember correctly. By the way this was the only issue I have ever had with my 8.1/allison.
The switch is known to be a problem but before replacing anything verify what your problem is before replacing anything as it may have nothing to do with your current code.
The switch is known to be a problem but before replacing anything verify what your problem is before replacing anything as it may have nothing to do with your current code.
Last edited by brian41; 12-03-2012 at 06:37 AM.
#37
Well guys just wanted to give everyone an update, I went to go to the auto part store to buy the neutral safety switch the other day but when I started it up the check engine light was not on anymore. Drove it around, towed the boat and the check engine light never turned back on. Wierd but I'm not complainaing, no more check engine light so that's good.
Boatnt, brian41 and everyone else, I wanted to thank you guys for helping me and guiding me in the right direction. You guys rock!!!
Boatnt, brian41 and everyone else, I wanted to thank you guys for helping me and guiding me in the right direction. You guys rock!!!
Last edited by 272bajadriver; 12-08-2012 at 01:25 PM.