Chevy & GMC Vans

Where may I obtain information on converting a 2002 Astro AWD to a 4x4?

well your on the right site that's for sure, i know there is some threads about putting new transfer cases in manuel shift 2 speed is a sticked topic in the 4X4 section and there are a couple about user controlled electrically engaged cases
this is the one i would like to do if my T-case ever dies
viewtopic.php?f=21&t=2586

Welcome buy the way

......welcome and I'll only do this once 'cause I'm nice and you're new...lol

Go to the Board Index scroll down to AWD/4X4 open that part of the forum and scroll to the fourth (4th) item down and that would be a good start on what you're after.... you'll also find most of the other related stuff (lifts etc) in this section.

Welcome! On your rig you have a couple of options. I chose the NP236 transfer case swap because it allowed me to keep AWD (best for snow) and also achieve 4hi and 4low. This is a bolt in t-case but requires a good bit of re-wiring, 25ish wires are either added or moved.

If you don't care about AWD then there are two other cases that are typically used, NP231 and NP233. While I haven't spent much time reading about these cases, my understanding is that the NP231 will be a tried and true manual t-case and the NP233 is push button shift but that folks like Herbie created a manual shifter to take the place of the electronics.

There are a couple of other options out there i believe that Photovan has another case that allowed awd.... this may have come with less wiring than the 236 but it required some t-case modifications if I remember right.

You can see the thread that I followed for my 236 swap here:
How to wire up a NP 236 in place of a 136.

Here is the document that I built to clean up that information:


Good Luck!