LLY: 2500HD 3500HD Transfer Case Differences if any

[raceghost]

Hi,

I have heard 2 different perspectives on the LLY Transfer case that comes in the 2005 HD's. COuple people say that there is no difference in the part numbers from a 2500 to a 3500 truck. Others say the 3500 is a more industrial or heavier duty unit than that in the 2500.

I have a 2005 2500HD
Here is my issue, Replaced the seal in the yoke 6 months ago due to leaking. RIght away it was leaking again, and it looks as though the transfer case needs internal work, its whining now, and does some weird noises when you engage 4 Hi to 4 LO, and utilize 4 lo.

I am just curious if as an upgrade, a 3500 is a better unit, and worth it to put in, or if there are any benefits at all?

Also, if it is a worthy upgrade, do I need to do anything to the TCCM to get it to work in the 2500?

Thanks in advance,

 

[gmac32]

No difference between the two

 

[Tothemax]

^x2 there the same

 

[raceghost]

Thanks guys

 

[THEFERMANATOR]

If it has an allison or zf6, the 2500hd got the same np261/263xhd case as the 3500. The confusion comes in with the 6.0l. The 6.0l/4l80e in a 2500hd got a np261/263hd, BUT for a few years the 3500's with a 6.0l/4l80e also got the np261/263xhd transfer case. The np261/263xhd case can be easily identified by the LARGE 29 spline output shaft, the np261/263hd case only got a 32 spline output shaft that is almost a 1/4" smaller in diameter. You have to watch out because all allison's and zf6's had 29 spline output's, but the 4l80e only had a 32 spline. So it is possible to find a np261/263xhd transfer case that won't directly bolt in. They're RARE, but do exist as I know somebody who needed one, and could NOT find one.

So some 2500hd's did have a lighter duty transfer case than there 3500 counter part. If it has a 8 lug 9.5"/10.5" rear axle it got the hd case, but if it had a 11.5" rear axle it got the xhd.

 

[weazel]

Out of curiosity, were there any changes from say the LLY or earlier duramax/ Allison’s to the later, say lmm year model transfer cases?

 

[Chevy1925]

Out of curiosity, were there any changes from say the LLY or earlier duramax/ Allison’s to the later, say lmm year model transfer cases?

yes, borg warner bought out new process and now supplies a different case than the NP that came in earlier models. I want to say 08 and up got the BW cases but im not 100% on that.

 

[Mike L.]

07.5 ( new body style ) got the AMA transfer case.

 

[Dozerboy]

Isn’t the case the same it’s just aluminum instead of magnesium?


Sent from my iPhone using Tapatalk

 

[Chevy1925]

Isn’t the case the same it’s just aluminum instead of magnesium?


Sent from my iPhone using Tapatalk

na, completely different looking. 06-07 were the only ones with aluminum cases

 

[THEFERMANATOR]

07.5-10 got the aluminum case transfer case. Very simiar to what was used in the 07 and older. It was 11 when GM changed transfer cases and went to the different bolt pattern.

 

[raceghost]

Great info, thanks guys. Mine is the LLY. By chance do the later better transfer cases fit? I am assuming not since I read different bolt pattern and all...