1989- RS to 4x4 swap list

[markmitch]

My 89 Astro RS has had many modifications over the years and is close to being done (surprised?) so to keep me going I decided to buy an AWD frame and take it to the next level. I have a list and pictures of what I need and what I wish to do started and will post it here and as I purchase things I will add those pics too.
My ideas so far: Front awd frame from a newer Astro/Safari from pick n pull will be stripped at the yard and will cost approximately 100 bucks. Front axle from 1994 to 2004 S-10 Blazer with 4.3/5 speed trans (cast iron instead of aluminum) stock from suspension from same frame-no clue on cost yet., I will be using a 4x4 transfer from an S-10 cost is 180.00 pnp. I will need to get a 700R4 case somewhere to remove my guts into since my transmission is a fresh rebuild basically. I will post more info as I go.. This will be a slow process as money comes available. I already added steel rear springs and 11" drums so that is done. Left kit will come last. Thanks for reading, Mark

[Mmusicman]

Front awd frame (stripped at the yard)...Front axle from Blazer...5 speed trans ... suspension from same frame...4x4 transfer...700R4 case... already added steel rear springs and 11" drums...Lift kit...

Yikes! It HURTS me just thinking about ALL this work!!
In my life now.. I'm looking for ways to do less hard work, not more.
Projects can be fun (as long as they don't take years to accomplish)

Personally, I'd just buy a later model AWD.
I keep seeing people getting crazy steals on them.

But we'll watch!
Good luck.

[markmitch]

A few pictures.

[markmitch]

The bravada shaft shown in the pictures is not needed on the Astro because they are the same however if one wishes to use the cast iron S-10 front diff you should swap the shaft from the astro diff to the s-10 diff. Just learned this on one of the s-10 sites.

[markmitch]

I just found out there are a few choices on the transfer cases, as I have read here on this site many use the 233. I read that in the S-10 up till 1997 they used a np 231HD transfer case that appears to be the strongest case available. I need to do more reading but at this point I think this will be my best option. I think for right now I need to get the front frame from our 98 and use it with the stock transfer case a modified oil pan for my 350 and work on getting these ready first. Which includes a body lift kit. Once this is done I will also have to revisit my spare tire carrier to handle a full sized or at least a full height spare. Maybe get a stock spare tire wheel and see if I can find a skinny but taller tire for it.

[backinabox]

Awesome project Mark. I'm looking forward to your progress and very envious....

[markmitch]

its a slow process, but I did get a 98 AWD donar for 400 bucks recently.

[backinabox]

wow that was a score

[markmitch]

Its kinda odd but in California there are like 20 or more pick n pull yards yet not one has a 2nd gen S-10. quite a few 1st gen vans but not one second gen S-10 truck or blazer.

[markmitch]

After looking at different oil pans online for the 4x4 swap with V8 I Think one from an older V8 may work but I will wait till I get the frame out and an engine block set in place prior to spending money. The older 4x4 GM trucks had a solid front axle and wouldn't that mean more to clearance with the oil pan?

[markmitch]

Looks like the pan will have to be made using two pick n pull steel 4.3 oil pans. I found this sticker I will order to add to my van when its done.

[Mmusicman]

I have read here on this site many use the 233. I read that in the S-10 up till 1997 they used a np 231HD transfer case that appears to be the strongest case available..

It is my understanding that the earlier 231 cases (used on lightweight Jeeps and S10's) were weak (smaller width chain), and the later model 231 may be stronger (hense the 231HD?). It is also my understanding that the later 231 case and 233 case are essentially the same (both using wider chain), with the only main difference being the 233 is electronically shifted. This would make the identical 233 case ALSO the strongest case available. At least this is my understanding and recollection, it's been a while.

It's interesting that the 231 is always well represented on most 4x4 sites, and often the 233 has less info, or sometimes is even left out of some listings of NP (National Process) cases.

The advantage of the 233C case (vs the 231 case) is that it is 100% GM directly interchangeable with the Astro 136 AWD case. Bolt patterns identical, lengths identical, output shafts, yokes, and seals identical. Both rear AND front AWD drive-shafts directly fit the 233C without any changes whatsoever. I believe the 231 case has a different front yoke output which bolts up, instead of using the slip yoke (not sure if this is the case with the S10). Then of course there is the issue of whether you have the stronger 231 case or the weaker one. This is not an issue with the 233. Utilized on later Chevy Blazers.. this is always a good interchangeable upgrade choice.

The ONLY downside of the 233 is converting to, and making, a manual shift bracket.
But apparently all the SERIOUS Blazer guys do it too!

Here's mine:

[markmitch]

Thank you for you info I did not know that about the 233. I am not really planning on an serious off roading but my house in New Hampshire has 10.5 acres and I would love to be able to drive around the property. in the summer I can actually cut trees down and make trails over to and around the island. If I build it strong there should be no problems doing this. So I will cut and paste your info and print it for my note book. Do you have 4lo with your set up?

[90safari]

Mark, since you've already rebuilt your existing 700R4 (instead of looking for another one/case), why not remove the guts from it, and swap the out put shaft and just reassemble it? I'm sure you've checked that case out thoroughly, and would be nice and clean inside. Just asking is all.

[markmitch]

Yes I looked into that myself, I will be doing just that the short shaft from one site brand new is on sale too. Possibly get it next month. I am building a wooden box out of pallets to store all the parts till spring. The box will be outside under a tarp since my garage is full. Damn grown kids think we are there personal storage place. It will be off the ground about a foot and covered with a new hd tarp.

[backinabox]

It's sad to think how close winter is now, I'm really feeling it with the cooler weather and shorter days. I'm trying to get mine back on the ground so I can move it into my Canopy/Garage for the next several months, I just sold my favorite bike to make room for the van...

[markmitch]

funny thing we had a dog house given to us and its not being used to since it has a roof on it like a regular house I am gonna put all my parts that fit into the dog house and nail a piece of plywood over the door and leave it till spring.

[markmitch]

So far I have the frame, with front axle, I added new poly bushings to the front axle, I have new poly mounts with 1/4 inch spacers for the engine, I already have steel springs from a 2000 Astro in pnp a few years ago on my 89 so that is done except I will be adding a leaf and possibly shackles. The 98 had all new shocks and the front brake parts seem to be in great condition so I am good there for now. I have the 2" body pucks but no bolts yet. I found an oil pan for my v8 I will be getting it at the end of the month. I will find either a 231 or 233 transfer then figure out the driveshaft situation. I will keep the rear axle from the 98 so I can rebuild it later and put some sort of locker in it. I did find a used short shaft for the output of my 700R4 for 20 bucks so I ordered it. I am thinking about ordering pre bent brake lines for this swap too. Anyone done that? Thanks for reading, Mark

[markmitch]

New (to me ) mirrors I got from another member-I figure they will be better for off roading since they are not all plastic.

[markmitch]

I will start taking the 89 apart again to swap the frames, I still need the adapter that bolts between the 700R4 and the bw 4472 transfer case which I am going to use till I get to NH along with the 4 new 215/75R15 tires that were on the 98 when I bought it. I am waiting for a new tool I ordered to check the pressure on the transmission prior to pulling it apart to swap the output shaft. Once I get the pressure test done I will start draining the coolant into a new container to reuse cause its brand new. I bought paint filters to run it through prior to re- use. I removed all the stuff I had stored inside the van and I will remove the seats to make it easier to put all the parts inside the van in cardboard boxes to keep it close and not lose anything. I also bought dollar store ziplock bags and a new sharpie. I will take pictures and post potential problems as I go. Thanks for reading, Mark