4l60E to 4l80E swap Transfercase questions

[907Ryan]

So i am swapping my 01 silverado short bed 5.3/4l60E 4x4 to a 2004 GMC 2500hd 6.0/4L80E. I have got most of the engine/transmission questions and issues sorted. I am trying to figure out a couple of last minute things with the transfer case.

 

I have both transfer cases from both trucks. I have read some things about different output shafts for the 4l60E and 4L80E.

The 2001 was 4x4 push button auto.  The 2005 Has push button 4hi-low but not the auto fuction.

I guess my question is can i just use the Transfercase that was already mated up to the 4l80E with modifications to the transfercase support/driveshaft. Or do i need to swap some parts into the 4l80E (32 spline input shaft for the transfer case) and use the case from the 4l60E truck. I know that with the swap people have done it still shifts back the transfercase a like 1.5-2.5" and that required modifying/moving  the mount. I already intend to by the cross member mount for the 4L80E transmission. Is there something similar i would need to get for the transfercase cross member or is it as simple as shifting it back. The forums on these get a little messy. 

I know ill need different drive shafts, shorter in back- longer in front.

I had also read issues with the driveshaft/joints. The transfercase from the 4l80E is mated to an 8 lug read end and the joints are different than a rear end from a 1500, is that correct? Is that one of  the reasons to swap output shafts in the transmission and us the 4l60E transfercase instead?

Last, is there issues with the harness between the two transfer cases. I did by the harness adapter for the 4L60E swap to the 4l80E swap (this was before i knew you could move around pins and such). Are there similar things that will need to be done for the transfercase.

 

Any information on this would be amazing.

 

[davester]

I would double-check the spline count/diameter for in the input and output shafts, I think they are different between the NP263 (or whatever it is for the one with the auto function) and the NP263HD.  And you'll likely also need to swap the front diff over as well (hopefully it has the same ratio as the rear of the 2500).

[David89GMC]

Check out Novak's website. They have all you need to know, and can provide whatever parts may be required. Surprised you didn't know about Novak