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Discussion Starter · #1 ·
Hi guys I'm new to the diesel world but I've always loved diesels. I finally got an 04 2500 HD 6.6 duramax. I've had lots of trouble but everything is about fixed now. Except what I believe the wastegate actuator. A friend suggested this. But I'll b driving 30 to 40 mph and the truck will by itself go into neutral and it'll rev up bc I don't catch it in time to let of the pedal, and I'll have to wait for it to calm down then I can try to accelerate again. Sometimes it'll do it again immediately and other times it'll wait and do it a mile down the road. If I'm going 65 or 70 plus mph it'll do it more frequently. And lastly if I don't let off the pedal quick enough it'll rev a little longer the check engine light will come on and say shift inhibitor something and the light will stay on for about 3 days or so and go off by itself. While the lights on I stop at a sign I've got to give it a lot of fuel to get going like I'm pulling a heavy load. This is so aggravating please guys help me, anybody experience this and what can I do to fix it????
 

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Hi guys I'm new to the diesel world but I've always loved diesels. I finally got an 04 2500 HD 6.6 duramax. I've had lots of trouble but everything is about fixed now. Except what I believe the wastegate actuator. A friend suggested this. But I'll b driving 30 to 40 mph and the truck will by itself go into neutral and it'll rev up bc I don't catch it in time to let of the pedal, and I'll have to wait for it to calm down then I can try to accelerate again. Sometimes it'll do it again immediately and other times it'll wait and do it a mile down the road. If I'm going 65 or 70 plus mph it'll do it more frequently. And lastly if I don't let off the pedal quick enough it'll rev a little longer the check engine light will come on and say shift inhibitor something and the light will stay on for about 3 days or so and go off by itself. While the lights on I stop at a sign I've got to give it a lot of fuel to get going like I'm pulling a heavy load. This is so aggravating please guys help me, anybody experience this and what can I do to fix it????
welcome, by the way, this is not the correct section for this, so your post will probably get moved, you are in the forum help section for issues with the forum, there are sections below based on the year of your truck, as well as a 911 section for issues that are immobilizing your vehicle.

As for your issue, could have a couple different things going on. The shifting issue used to happen to me every now and then on my 01, it ended up being a bad neutral safety backup up switch (NSBU) Its very easy to replace, and costs 50-80 bucks or so for the part. If your slipping into neutral there is a good chance that this switch is the problem, otherwise the issue is probably with the transmission.

Just to clarify, its for sure going to neutral right, not 3rd gear? dropping to 3rd gear would be a limp condition for the transmission and would indicate that you are slipping clutches.

As for the hard to get going, you mentioned a waste gate issue, if the gate were stuck open it would make the truck feel heavy for lack of a better word, power would be low, acceleration would be poor, and it would chug around. This could also be due to a boost leak, which is not uncommon. Usually you will blow the boot at the top of the engine off the tube (can be other boots, but this is the one ive usually seen pop off) or you may have rubbed a hole through the intercooler tube on the driver side of the truck where it rubs on the power steering line mount.

Do you have any other info like codes, vehicle data like rail pressure, balance rated ect? The more info you can provide the better quality your answers will be. Without knowing more these would be my guesses towards your problem based on what is a common failure and cheap / easy to repair or check.
 

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Discussion Starter · #3 ·
Well it doesn't go to neutral I meant to say it stays in drive but is like in neutral and I hear like an air line being released sound. Then when the rev calms down I just try to accelerate again and move on. And the truck works great until this happens it's never sluggish or chug along it even does good when the engine light is on. Its just when I stop completely while the engine light is on it'll take a lot of fuel accelerating to move at first, after that it drives fine. Thank u for the tip, I'll remember next post to place it in the right area. I'm working on the navigation of the forum.
 

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Discussion Starter · #4 ·
Ok update. I just went to pick up my son the truck did its normal symptoms and the check engine light is on now, while it's on the truck doesn't do the symptoms anymore. But the dash says, range shift inhibited. And so I'll cruising at 35 40 steady the truck will shimmy or jerk a little here and there like I'm running over rough terrain. Then I get in the driveway and I have no reverse I put back in drive and it hits hard. I did that twice to make sure it wasn't a one time thing and it does that everytime. Thats all I got that's everything my truck does I hope that's more info thanks for any help to fix this.
 

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Ok update. I just went to pick up my son the truck did its normal symptoms and the check engine light is on now, while it's on the truck doesn't do the symptoms anymore. But the dash says, range shift inhibited. And so I'll cruising at 35 40 steady the truck will shimmy or jerk a little here and there like I'm running over rough terrain. Then I get in the driveway and I have no reverse I put back in drive and it hits hard. I did that twice to make sure it wasn't a one time thing and it does that everytime. Thats all I got that's everything my truck does I hope that's more info thanks for any help to fix this.
im still questioning if the NSBU switch might be bad, and you have an additional issue, but im not sure, it might be worth posting in the transmission section of the forum, theres a few really knowledgeable guys in there that might be able to answer the question better. the NSBU would not explain all of your symptoms as far as i am aware.
 
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