So I have a 05 2500hd Duramax with the Allison trans and it has a 4wd issue. Sometimes the 4wd will work or at least I believe it is working, if I don't have the engine on and out the truck in neutral then hit 4h or 4l I can hear the solenoids/motors switching it and I believe the axle disconnect and the transfer case are working, I know the transfer case is working because just going 4h to 4l I can hear it and it seemed to be making noise from 2h to 4h but after driving it around or just switching between 4wd and 2wd a few times I get a service 4wd on the dash and either no lights on the 4x4 switch or the 2h light will be on but nothing happens if I hit the buttons. Curious if anyone knows where exactly is the best spot to start I have already replaced the switch and it does the same thing.
2005 GMC 2500hd lly allison 4wd issue.
- Thread starter MrV
- Start date
Welcome to the forum from Oregon.
If you are in a "salt on the roads" area of Oklahoma, it can pay to remove the encoder/transfer case motor and inspect. Clean and lube where you can and also check for corrosion on the connector.
If you are in a "salt on the roads" area of Oklahoma, it can pay to remove the encoder/transfer case motor and inspect. Clean and lube where you can and also check for corrosion on the connector.
We don't salt our roads here so that is a non issue, I just messed with the truck more and got it to work again consistently so I guess I will have to see if it holds up, I have never been a fan of the electronic 4x4 systems and all my trucks are manual case and manual hubs.
So, you are saying that your 2005 Duramax is a manual case and manual hubs? The 20 years of age, alone, can be a reason to pull the motor and inspect and inspect the connector.
Cadillacmak
Well-Known Member
I am with you on that, I prefer manual also! I am betting the encoder motor needs cleaned and lubed, or replaced like @ORVietVet said. That's where I would start.
No it's the push button 4x4, I will pull the motor and connector next week probably. Is that just somewhere on the transfer case? I know this truck recently had the trans and transfer case replaced before I started working here on it truck only has 250k miles lol.
It looks like this: https://www.rockauto.com/en/moreinfo.php?pk=8136412&cc=1431220&pt=10323&jsn=700
Be sure to look inside when the motor is removed. That area can be cleaned and get fresh lube, too.
Be sure to look inside when the motor is removed. That area can be cleaned and get fresh lube, too.
Is there a preferred type of lube or just something like bearing grease.
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