OK, thanks for the advice, everyone. I was told the level 7 4L65E held good power in trucks running 10sec and Vettes running 8 sec. I was trying to avoid the hassle of adapters and modifying drive shafts.

I searched around for info about 4L80E swap but every time it gets more complicated because of the different transfer cases.

My truck is 2003 Chevy Silverado LS trim 1500 RCSB stepside. It came stock with floor shifter transfer case.

So, here are my questions:

• Can anyone tell me the part# for the correct transfer case input shaft, 32 spline input shaft, that I should install in my transfer case? I have 32 spline input shaft PN 88962329. But by looking at different threads here I found people using different shaft PN 12386258, 12384969.
  
  
• What is the part # for the 4L80E to my transfer case adapter? I understand the 4L80E uses different adapter than the 4L60/65E to mate to the transfer case.
  
  
• Can a 2WD 4L80E fit or I must use 4WD 4L80E? A local guy is selling bran new RPM 4L80E level 4, I think, but it's 2WD. So, if I remove the tail cover, can I use that 2WD 4L80E for the swap.

 

Checked under the truck. My transfer case is tagged NP261.

The input shaft PN 88962329 will not fit as it is for NP241. From searching, the bearing is different.

 

https://www.performancetrucks.net/fo...-4l80e-424904/

Read thru this epic thread bud , this has been pretty much the bible for all of us who have done 80e swaps.

Modding the crossmember can be done diff but you'll get the idea and where to get your parts/ adaptors.

As far as the 2wd 80 all that would need changed would output shaft AFAIK .

 

80e and HD2 Shift Kit.

 

You would use the regular 4L80e tcase adapter. It is the same 6 bolt pattern for your tcase. It is a very simple swap.

 

Is this what your running??

 

I went over this thread before but I am confused about 32 spline input shaft. The one I have is PN 88962329. I read that it's for NP241, 246 autotrac and it might not fit NP261, manual shifted transfer case, because of different pilot bearing size.

Can any one confirm fitment of the input gear if it came with pilot bearing. Mine came with bearing installed in the input shaft.

Do I need to buy another input shaft.

 

Is there a PN for the tans/tc adapter?

Is the 80E input/output shaft stronger that 60E shaft? Does it need billet shafts?

I broke my stock 60 input shaft and now have billet input/output shafts in my 60E.

 

How do I know which bearing this input shaft has, from the PN? .630" or .940"?

Or how to measure it?

I believe NP261 will need the .630" bearing input shaft. Are the two shafts the same and simple bearing swap from my old stock shaft will resolve it??