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Transfer case info

Doonatic
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Doonatic Enthusiast

Doonatic

Posted
Posted

Hey yall, got a question for you. For the 2003 2500hd’s, Chevy offered 3 different types of transfer cases. Does anyone know how to identify which transfer case is installed in the vehicle one may have.

 

I am moving into my 3RD transfer case (factory installed chain ground a hole through the case years ago, dealer installed a “new” used one, and now this one will not engage reverse). I am vigorously searching for a new case NOW, because I am afraid my vehicle will leave me stranded very soon. (Side note: I get a grinding noise-like the chain is rubbing ONLY during coasting.)

 

So if anyone can help me find the part numbers or the direction to locate said replacement parts, that would be amazing.

OldGuy96 Enthusiast

OldGuy96

Posted
Posted

Are you sure it's the transfer case? If it will engage 4WD Hi and Lo, then the transfer case isn't your problem. If the truck won't go into reverse, you probably have a transmission problem.

PTXer Enthusiast

PTXer

Posted
Posted

What is your RPO code?  That should narrow it down.  It might be stamped/labeled on the case as well.

Doonatic Enthusiast

Doonatic

Posted
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Posted
21 hours ago, OldGuy96 said:

Are you sure it's the transfer case? If it will engage 4WD Hi and Lo, then the transfer case isn't your problem. If the truck won't go into reverse, you probably have a transmission problem.

Old guy, i thought that as well, however when it is in reverse the noise that is emmitting from underneath is coming from the transfer case, not the transmission. Its as if it is a solenoid motor that is not engaging.

Doonatic Enthusiast

Doonatic

Posted
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Posted
8 hours ago, PTXer said:

What is your RPO code?  That should narrow it down.  It might be stamped/labeled on the case as well.

RPO code?

newdude Senior Enthusiast

newdude

Posted
Posted (edited)

GM used two transfer cases in 2500HD trucks (2001-2007 classic), the NVG 261 and NVG 263 transfer case.  The 261 is the manual shift 2 speed case (floor shift), RPO code on the build label is NP2.  The 263 case is the electronic shift 2 speed case, RPO code on the build label NP1. 

 

There is some internal differences in the cases between the gas mated to 4L80, and gas/diesel mated to Allison cases in terms of gears, chains, input shafts, etc.   

 

I believe ones bolted to the Allison had "HD" or "XHD" tagged at the end of the case number on the NVG stamp on the rear.  NVG261/3 XHD/NVG261/3 HD. 

Edited by newdude
carkhz316 Enthusiast

carkhz316

Posted
Posted
3 hours ago, newdude said:

GM used two transfer cases in 2500HD trucks (2001-2007 classic), the NVG 261 and NVG 263 transfer case.  The 261 is the manual shift 2 speed case (floor shift), RPO code on the build label is NP2.  The 263 case is the electronic shift 2 speed case, RPO code on the build label NP1. 

 

There is some internal differences in the cases between the gas mated to 4L80, and gas/diesel mated to Allison cases in terms of gears, chains, input shafts, etc.   

 

I believe ones bolted to the Allison had "HD" or "XHD" tagged at the end of the case number on the NVG stamp on the rear.  NVG261/3 XHD/NVG261/3 HD. 

Just tagging on to this to confirm what you mentioned about the Allison-equipped trucks (8.1/ Duramax). They are 261/3 XHD as you stated. Only real differences with the XHD variants are the larger output shafts, and different oil pumps. Otherwise, most of the guts are the same.

  • Like 1
newdude Senior Enthusiast

newdude

Posted
Posted
10 hours ago, carkhz316 said:

Just tagging on to this to confirm what you mentioned about the Allison-equipped trucks (8.1/ Duramax). They are 261/3 XHD as you stated. Only real differences with the XHD variants are the larger output shafts, and different oil pumps. Otherwise, most of the guts are the same.

 

Thanks for the clarification.  :thumbs:

  • Like 1
  • 3 years later...
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 5/23/2022 at 8:32 AM, LarsonFarms said:

Will a 2005 transfer case work in a 2008 Chevy 1500?

It is not a direct bolt on, plug in and go.  I would say no, but exactly which transfer cases are in question here?  My brain thinks of the 246 and MP3023 which are electronic.

  • 2 years later...
Steven suzor New Member

Steven suzor

Posted
Posted

Mine is stuck in 4 low will not come out. Sounded like an explosion constant grinding even when truck is in park.  My truck is still in neutral and making the grinding noise. 2003 GMC Sierra 1500

davester Senior Enthusiast

davester

Posted
Posted

No, get the same TC as what's in the truck.

 

You might be able to manually shift what mode the TC is in, by removing the encoder from it, then manually rotating the post to the mode you want.  It may take some fiddling ton find which position is for 2hi

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