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Official Cactus Dealer
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Discussion Starter #1
OK so my dad has an 06 duramax with an auto allison 6 speed trans with a bit of a starting issue. When he hits the key to start it sounds like the starter is grinding on the flywheel but wont engage. If he pulls up of the shifter or drops in all the way down to first and slowly brings it back to nuetral it will start normally. He took it back to the dealer he got it from but all they will tell him is it could be the shift cable or it could be a switch in the trans. Anyone ever deal with this before? I can get the parts and change them out but i dont want to just start throwing money he doesnt have at it. Any way to narrow down what it could be? Thanks
 

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OK so my dad has an 06 duramax with an auto allison 6 speed trans with a bit of a starting issue. When he hits the key to start it sounds like the starter is grinding on the flywheel but wont engage. If he pulls up of the shifter or drops in all the way down to first and slowly brings it back to nuetral it will start normally. He took it back to the dealer he got it from but all they will tell him is it could be the shift cable or it could be a switch in the trans. Anyone ever deal with this before? I can get the parts and change them out but i dont want to just start throwing money he doesnt have at it. Any way to narrow down what it could be? Thanks
If you don't get a good answer here I recommend asking this question on dieselplace.com its a Duramax specific site.
 

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Motorboatin SOB
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So your thinking its almost not going all the way into park, and moving it to neutral it will start fine?

If thats the case it probably needs that shift select sensor on the side of the tranny. I dont know this for sure and have never had to do it on either of dads duramax's, but Ive heard/read that when those go bad they do weird shit.
 

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On the early 2000s, the shift select deal was on the outside like a 4l60, and they were susceptible to corrosion etc. I was thinking on the newer ones that they were inside the transmission?
 

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Official Cactus Dealer
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Discussion Starter #6
If he does what? I Didn't quite catch that?
While the shifter is in park Pull up on the lever (towards the roof) sometimes that works if not shift all the way down to first gear and slowly go gear by gear back to nuetral and most of the time that takes care of it.
 

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There is an internal shift position switch inside the 6 speed transmission but I believe there is another park indicator in the steering column. The reason I believe there are 2 is because the line that indicates what gear your in on the dash will flicker when in park if I barely wiggle the shifter. This may be causing the problem. Try holding up on the shift lever and make sure you have a steady line under the P on the display. This is a new one on me!
 

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You would think if the sensor wasn't reading park or neutral that the starter shouldn't engage at all.

But you said it was grinding, which means it is reading park or neutral.

Doesn't sound like an indicator problem to me, sounds like starter is not kicking out like it should.
 

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Discussion Starter #9
You would think if the sensor wasn't reading park or neutral that the starter shouldn't engage at all.

But you said it was grinding, which means it is reading park or neutral.

Doesn't sound like an indicator problem to me, sounds like starter is not kicking out like it should.
Thats what I thought at first too but if you just keep trying it without touching the shift lever it will continue to do it. unless it could just be coincidence that it kicks in when playing with the shifter
 

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Theres an IMS(internal mode switch) inside the trans that tells the TCM what gear the trans is physically in. It also tells the ECM and BCM if it is in park or nuetral to allow it to engage teh starter relay. Moving the shifter would have no bearing other than to allow it to start or not. It is either there or not. There have been quite a few instances of the starter bendix sticking on trucks over 100K miles, and sounds like what your experiencing. I would suggest next time it does it, take a rubber mallet and tap the starter, the small tap will most likely allow it to start normally.
 

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Just remember if you decide to attempt this IMS..The valvebody has to come down because there is a small pin that holds the shaft in under the valvebody....not a huge pain but a hell of a lot more than just dropping the pan....
 

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Just remember if you decide to attempt this IMS..The valvebody has to come down because there is a small pin that holds the shaft in under the valvebody....not a huge pain but a hell of a lot more than just dropping the pan....
And they RARELY fail. if the OPS was the problem, the ECM wouldn't trigger the starter relay at all. The IMS sends a signal to the TCM, that sends a signal over the databus that is read by the BCM and ECM, and if the BCM clears it the ECM will trigger the starter relay that in turns sends power to the starter solenoid that engages the starter. I see NO WAY the IMS could cause what he is experiencing.
 

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Go to dieselplace.com . They will have all the answers for any diesel period . That's where I found the ice pick trick for the injector harnesses on my duramax.
 

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Discussion Starter #14
Ok so after looking at it Its the starter. It not kicking the bendix out all the way. Now comes the fun part of changing the bugger out. From what ive seen it can be a big pain in the ass to do
 

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Spend the money and buy a new hitachi starter or delco reman from the dealer. Starter change is way easier to do by removing the front pipe from the down pipe. Problem has been that the part store reman starters have a 4-5 mm shorter starter gear and they do not fully engage with the flywheel so you will be changing it back out in a year or less and they will not warranty it saying you installed it incorrectly and that is why the leading edge of the starter gear is warn down.
 

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Theres an IMS(internal mode switch) inside the trans that tells the TCM what gear the trans is physically in. It also tells the ECM and BCM if it is in park or nuetral to allow it to engage teh starter relay. Moving the shifter would have no bearing other than to allow it to start or not. It is either there or not. There have been quite a few instances of the starter bendix sticking on trucks over 100K miles, and sounds like what your experiencing. I would suggest next time it does it, take a rubber mallet and tap the starter, the small tap will most likely allow it to start normally.

Tried that on the kids work truck , wound up having to roll the crank and it started . I need to check the flywheel to see if some teeth are missing , the starter checked out fine . This thing needs work bad , one problem causing it all and his boss is to cheap to fix it , LOL !
 

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Spend the money and buy a new hitachi starter or delco reman from the dealer. Starter change is way easier to do by removing the front pipe from the down pipe. Problem has been that the part store reman starters have a 4-5 mm shorter starter gear and they do not fully engage with the flywheel so you will be changing it back out in a year or less and they will not warranty it saying you installed it incorrectly and that is why the leading edge of the starter gear is warn down.
This and the inner fender well , oh and the bottom bolt is a bitch , LOL !
 

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Discussion Starter #20
Spend the money and buy a new hitachi starter or delco reman from the dealer. Starter change is way easier to do by removing the front pipe from the down pipe. Problem has been that the part store reman starters have a 4-5 mm shorter starter gear and they do not fully engage with the flywheel so you will be changing it back out in a year or less and they will not warranty it saying you installed it incorrectly and that is why the leading edge of the starter gear is warn down.
I work for a delco dealer and already know i got one on the shelf8)
 
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