About 6 months ago I had found a website in which someone documented their process of converting an AWD Chevy Express or GMC Savana to real 4wd. The process was basically "unbolt AWD Tcase, bolt in Tcase from 4wd chevy pickup, add shift cable."
They used the borg warner 4wd case from a truck which is externally identical to the AWD case in the van so it was a true bolt-in. No modifications to the driveshafts.
I found one with a similar conversion on expedition portal's forum, but they used an NP241 and had to do a custom front driveshaft.
Can anyone help me find that other page? I have searched so much for it that I fear it may no longer exist.
Mr_Asa
UltraDork
2/7/21 1:19 p.m.
Digging around, I think I found that the NP246 is a straight replacement for the BW4473 which may be in your van. May help?
Edit: How much help is this? https://www.sportsmobileforum.com/forums/f10/4x4-vs-awd-27338-2.html#post285475
Edit the second, the Editing: also, if you do have the BW4473, it sound like a lemon https://www.gmtruckclub.com/threads/2004-savana-awd-transfer-case-problems.36295/
THis is good stuff. I have actually found all of those pages at one time or another. The NP246 swap is close, but they are a direct swap-in on the Astro/Safari which (I think) starts out with a different BW case? I forget.
The Astro/Safari used a BW4472 till 98(that’s what my parts van is) and a NV136 (computer controlled clutches) from 99 on.
IIRC, pretty much the same as the full size, but not a direct bolt in.
I know much less about the full size...
It's frustrating. Engines and transmissions, I know like the back of my hand. Transfer cases? No clue what fits what.