Starting my build


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Captn. Crunch
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Starting my build

Post by Captn. Crunch »

Hey
So I love my 99 AWD and have been figuring out what I want to do to my rig. So far I have modified my rear end by installing a zexel Torsen rear differential. This gets me from an open diff to limited slip/posi track. I have also done the 2" body lift and S-10 rear leaf spring swap. I have put on a set of wrangler 29" tires and started swapping out the front end parts with Moog components.
I have picked up an np236 transfer case and the associated computer parts to control it. I will be rebuilding to case here shortly before installing. I will use the exsisting encoder motor for the time being to maintain AWD and work on accessing low range a little further down the road.
I have found and posted here a limited slip option for our 7.2" front diff. Jeff at Engineered Performance needs the center chunk out of the diff for a week or so to modify it to a LSD. Not wanting to take my DD off the road I thought it best to buy another front diff. While surfing other forums I became aware of a very cool piece of GM history. If you bought an S-10 4x4 with a manual five speed and the three button np231 transfer case your truck came through with a cast iron front diff vs the aluminum that came in everything else.
For the last year or so I have been checking the national used parts registry for one of these. They are rare and expensive. Last week I tried again and a yard in Pa. quoted me $250.00 shipped so I bought it. That's half price compared to previous quotes!
I will be sending the center chunk to Ga. for upgrading and installing this cast LSD in my van. This will give me power to all four corners. I then have to start a slow methodical addition of electronics to incorporate the two speed transfer case with the auto four wheel drive option. I haven't taken any pics of what I've done so far as its all been documented on this forum already. Once I get into uncharted waters I will keep you updated with lots of pics till then...
Last edited by Captn. Crunch on Wed Jul 02, 2014 2:42 am, edited 1 time in total.
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s
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Stroverlander
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Re: Starting my build

Post by Stroverlander »

Sounds like fun and looking forward to your progress reports!

I keep an eye out at the salvage yard for a ZR2 iron front differential but haven't come across one yet, great find! Is there website for Advanced Engineering and where are they located in Georgia?
2004 Astro LT AWD Stroverlander

Topic author
Captn. Crunch
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Re: Starting my build

Post by Captn. Crunch »

Engineered Performance
www.engineered.net/
Engineered Performance - Home of the EP Limited Slip Differential.
You visited this page on 6/17/14.
Sorry my bad I gave the wrong name. This is the place.
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

photo_van
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Location: 7000' in the Mountains of California
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Re: Starting my build

Post by photo_van »

Sounds good Captain. Aren't those front ends used in the Bravadas and syclones too?
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

Topic author
Captn. Crunch
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Re: Starting my build

Post by Captn. Crunch »

Sy/Ty's all came though with aluminum believe it or not. There is a poll over on zr2usa that runs down which trucks got the cast. Very select


http://www.zr2usa.com/mboard/index.php? ... howforum=4
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
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Re: Starting my build

Post by photo_van »

thanks for that link!
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

Topic author
Captn. Crunch
I sleep in my van
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Location: southeastern ct
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Re: Starting my build

Post by Captn. Crunch »

So I checked the tracking number for the diff and its sitting eight miles away for the long weekend. That's alright because I have plenty to do with the ball joint re-location, torsion bar crank and the np236 transfer case rebuild.
Small step backwards today as my ac compressor seized up and smoked me out of the van. Thankfully no flames. Buddy had a spare and we were back up in an hour
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s
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Stroverlander
I sleep in my van
Posts: 308
Joined: Fri Dec 16, 2011 4:18 pm

Re: Starting my build

Post by Stroverlander »

Looking forward to the NP236 rebuild and install as ultimately, this is the direction I want to go as well. :cheers:
2004 Astro LT AWD Stroverlander

Topic author
Captn. Crunch
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Re: Starting my build

Post by Captn. Crunch »

I was re-reading my post and noticed an error. The combination of five speed manual transmission and three button 4x4 np231 transfer case should read np233. My apologies
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Topic author
Captn. Crunch
I sleep in my van
Posts: 557
Joined: Wed Feb 01, 2012 12:10 pm
Location: southeastern ct
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Re: Starting my build

Post by Captn. Crunch »

Here's pics of the cast iron front diff and an np136 and np236 side by side
Attachments
image.jpg
image.jpg
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Topic author
Captn. Crunch
I sleep in my van
Posts: 557
Joined: Wed Feb 01, 2012 12:10 pm
Location: southeastern ct
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Re: Starting my build

Post by Captn. Crunch »

I picked up the two transfer cases because I have not been able to find any side by sides to put to rest any doubts the 236 is a straight bolt up operation. Both cases have their own small issues so I will be taking both apart side by side and constructing one good case with hi/lo range. I will initially use the encoder motor from the 136 and if all is well I will have exactly what I have right now-AWD. The next step will be to start swapping in the two speed electronics and start trying to access the low range.
The cast iron front diff is from a ZR2 S-10 so it has the 3.73 ratio already in my van. The center chunk is going to Performance Engineering for a limited slip upgrade. Then a front diff swap. I will use the two piece S-10 axle to maintain the power to only one wheel for road manners especially in low traction situations like snow. I can engage the fourth wheel with the pull of a cable to power up the fourth wheel for extreme traction situations.
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

photo_van
I sleep in my van
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Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
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Re: Starting my build

Post by photo_van »

Wow, those cases look identical. Are they both five bolt bolt up with the same clocking? (Assuming that later Astros are 5 bolt....)

Hope it works out, probably a lot easier then what I had to do with a '98 for AWD!
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710

Topic author
Captn. Crunch
I sleep in my van
Posts: 557
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Location: southeastern ct
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Re: Starting my build

Post by Captn. Crunch »

It appears the only difference is the one speed/two speed. The cases appear identical in every way. I will be opening them up and all will become clear
Attachments
image.jpg
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

Topic author
Captn. Crunch
I sleep in my van
Posts: 557
Joined: Wed Feb 01, 2012 12:10 pm
Location: southeastern ct
Has thanked: 1 time
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Re: Starting my build

Post by Captn. Crunch »

photo van your transfer case build was inspirational dude! That was some great build
Captn. Crunch
"I don't beat my rig-I use it to it's maximum potential"
1994 Safari conversion (sold) and miss'n it!
1999 Safari SLE AWD junked
2003 GMC Safari AWD SLT
cast iron Torsen equipped front diff
S-10 leafs-G80 rear w/3.73’s
2” body lift w/Falken Wildpeak AT’s

photo_van
I sleep in my van
Posts: 592
Joined: Wed May 18, 2011 4:38 pm
Location: 7000' in the Mountains of California
Been thanked: 3 times

Re: Starting my build

Post by photo_van »

thanks Cat'n. Looks like a cool project. :cheers:
1998 AWD/4WD
4" lift, 31x10.50's, NP 242j/c hybrid, 4.10 gears, S10 front disconnect, rack & pinion steering, trans cooler, rock sliders, ARB fridge, house battery and 100w solar, swing out rear rack with foldout camp table, bed and passenger swivel chair
dirt bag camping rig
1981 Toyota 4x4 pu
1974 John Deere 710
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