My 2000 AWD to Manual NP233 4x4 Upgrade!
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Great How-To, MMusicman!!! You mentioned more time on the write-up than the work, and we DO appreciate that. (with my typing , it be 'bout 4 to 1. Course, I work mighty slow sometimes, so maybe not!!!)
Fantastic work on the pictures, with circles, and arrows, and descriptions (on the back).
perfect place to mount the shifter. Very "clean."
Did not know the NP233 did not have neutral. Good info.
I VERY much like the fact that you intentionally did it all with "common-man" tools... Helps us "Common Folks" !!!!
Fantastic work on the pictures, with circles, and arrows, and descriptions (on the back).
perfect place to mount the shifter. Very "clean."
Did not know the NP233 did not have neutral. Good info.
I VERY much like the fact that you intentionally did it all with "common-man" tools... Helps us "Common Folks" !!!!
Thanks TowVan for the nice words. Yes my goal was to do the job with basic tools (no welding) and easy inexpensive supplies you can pick up at any local hardware store! The "shifter cable" from Summit for about $50 was about the only other real expense.
Regarding the manual "side of seat" shifter.. I couldn't be more pleased with the result! After some time has now passed and I've used it a few times... I wouldn't change a thing! It came out perfect for me! It's hidden out of the way.. yet right there easy to use when you need it.
The Liberty shifter is a good option too (particularly if you have captains chairs with swivel seats).. but as I've said it would have taken up valuable floor space (for me) and would have required a little more effort. It would have "looked cool" too.. but NO ONE ever sees it anyway besides me. I think my seat shifter looks pretty cool too. The main thing is that is works simple and flawlessly!
The 4x4 conversion has served my needs perfectly! AWD is probably a better option for average snow users.. but I needed a real 4x4 low range option for my specific needs. The real cool fact is... the 233 uses no electronic controllers, no sensors, no encoder motors, and no pre-loaded clutches that wear out... all these things that can and eventually do fail over time. Of course there are the other issues with shuddering on take-off and binding in turns.. all gone! It's awesome knowing I no longer have to deal with ANY of these things. Just pull a manual lever and go!
Here's a pretty cool video of my 4x4 in work use... towing a 5000lb lift slightly uphill in very soft dirt. I pull these type tow-lifts on occasion.. and many times in off-road places. This wasn't possible with the AWD which embarrassed and failed me miserably at this same work location previously.
Here's a link with more pics and video: I Did Some 4-Wheelin Today
...
Regarding the manual "side of seat" shifter.. I couldn't be more pleased with the result! After some time has now passed and I've used it a few times... I wouldn't change a thing! It came out perfect for me! It's hidden out of the way.. yet right there easy to use when you need it.
The Liberty shifter is a good option too (particularly if you have captains chairs with swivel seats).. but as I've said it would have taken up valuable floor space (for me) and would have required a little more effort. It would have "looked cool" too.. but NO ONE ever sees it anyway besides me. I think my seat shifter looks pretty cool too. The main thing is that is works simple and flawlessly!
The 4x4 conversion has served my needs perfectly! AWD is probably a better option for average snow users.. but I needed a real 4x4 low range option for my specific needs. The real cool fact is... the 233 uses no electronic controllers, no sensors, no encoder motors, and no pre-loaded clutches that wear out... all these things that can and eventually do fail over time. Of course there are the other issues with shuddering on take-off and binding in turns.. all gone! It's awesome knowing I no longer have to deal with ANY of these things. Just pull a manual lever and go!
Here's a pretty cool video of my 4x4 in work use... towing a 5000lb lift slightly uphill in very soft dirt. I pull these type tow-lifts on occasion.. and many times in off-road places. This wasn't possible with the AWD which embarrassed and failed me miserably at this same work location previously.
Here's a link with more pics and video: I Did Some 4-Wheelin Today
...
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1,205 Posts
I'm getting everything together to do this project. Found out I had wrong drive shaft and none of the local yards have an AWD of 1999 or later. So off to flea bay. I found one that says it is 31 spline. Can they just not count very well or is there really a 31 spline and a 32 spline for these vans?
That's been a well pondered question! But I'm pretty sure they ARE the same.
Best I can figure on 31/32 splines.. is that the 32nd spline is flat. Maybe for indexing purposes, but the output shaft on ours is not indexed. It seems the consensus is that they are 31 spline.
BTW.. you "could" buy just the correct yoke. But it would probably cost you more than the whole drive-shaft.
Best I can figure on 31/32 splines.. is that the 32nd spline is flat. Maybe for indexing purposes, but the output shaft on ours is not indexed. It seems the consensus is that they are 31 spline.
BTW.. you "could" buy just the correct yoke. But it would probably cost you more than the whole drive-shaft.
Well, well... it's finally my turn to do this upgrade!
I keep finding myself working on job-sites pulling heavy loads off-road desperately needing 4-LO range gearing and full time 4x4 operation. The 4.3 in the single high range AWD with taller tires and stock gears just isn't working well for me at all... it generates a lot of sudden heat... it struggles badly and is severely under-powered... and it REALLY puts a strain on the trans too. The AWD system has reliability and operational issues too, issues with sticking or failing encoder motors (99-up), issues with clutch-packs and wear, but most importantly lacks a very needed low-range gear.
I considered both the NP233 vs the 236 transfer cases... but since I do not live in snow country, I do not need the benefit of the auto AWD, or the complexities of the 236 installation. The simple drop-in NP233C was chosen!
I have also chosen to go with the "manual" shift conversion vs the electronic push-button shift, for both simplicity, dependability, and reliability.
I'm re-posting a couple of posts (from a couple different threads) so I have it all here in my build thread. This was the start topic...
NP233 vs NP236: https://www.astrosafari.com/viewtopic.p ... 9&t=135734
-------------------------------------------------------------
July 5, 2018:
UPDATE: My "new" 233 unit arrived today! :mrgreen:
Actual unit weighs only 68lbs... much lighter than I expected.
![]()
![]()
I purchased the unit though Ebay, $175 (including shipping)
This unit is from an 03 Blazer. I confirmed it has 32-spline output.
![]()
I've read there may be some case indexing issues old vs new.. I'l let you know how this one does.
The unit is light enough it can be lifted and carried with one hand.
I turned everything by hand and verified the 4x4 Hi/Lo selector is working.
![]()
The new basic gasket/seal kit arrived today as well... $12 on Amazon.
![]()
Now to fabricate my manual shifter.
I'm learning toward possibly something similar to this that "LiftedAWDAstro" did on the other site... but perhaps either a little shorter, or further back.
I will experiment with leverage lengths and angles once the cable is in place.
I have a box that sits in the center between the seats, so this really won't be visible.
![]()
Looks like I may go with this Lokar S-7100 cable kit ($50 from Summit) connected to a simple shifter mounted to the side of the driver seat facing forward. I think I'd prefer the shifter close as possible to the seat vs cutting open the floor.
This cable kit appears to have everything I'll need (except actual shifter lever)
![]()
But I'll probably take a visit to the junk yard just to see my other options.
I'm pretty excited about taking this to the next level!
See more at NP233 vs NP236: https://www.astrosafari.com/viewtopic.p ... 9&t=135734
-------------------------------------------------------------
July 7, 2018:
The new unit is here.. I'm just shopping for my best linkage solution. Still undecided on the Jeep Liberty shifter (found a nice one in JY yesterday).. or making my own (shifter mounted on the side of the seat base). The Liberty shifter will be the simpler and cheaper choice, and comes complete with everything I'll need. I'm probably going to go back and pull it Monday, regardless. The cable though the floor to a simple seat mounted shifter is my preferred choice. But once I cut the big opening in the floor, the choice will be made.
Mmusicman, thanks for the great write-up! I am getting ready to swap the transfer case in my 2001 Astro AWD for the NP233-C and need some help finding the right T-case.Well, well... it's finally my turn to do this upgrade!
I keep finding myself working on job-sites pulling heavy loads off-road desperately needing 4-LO range gearing and full time 4x4 operation. The 4.3 in the single high range AWD with taller tires and stock gears just isn't working well for me at all... it generates a lot of sudden heat... it struggles badly and is severely under-powered... and it REALLY puts a strain on the trans too. The AWD system has reliability and operational issues too, issues with sticking or failing encoder motors (99-up), issues with clutch-packs and wear, but most importantly lacks a very needed low-range gear.
I considered both the NP233 vs the 236 transfer cases... but since I do not live in snow country, I do not need the benefit of the auto AWD, or the complexities of the 236 installation. The simple drop-in NP233C was chosen!
I have also chosen to go with the "manual" shift conversion vs the electronic push-button shift, for both simplicity, dependability, and reliability.
I'm re-posting a couple of posts (from a couple different threads) so I have it all here in my build thread. This was the start topic...
NP233 vs NP236: https://www.astrosafari.com/viewtopic.p ... 9&t=135734
-------------------------------------------------------------
July 5, 2018:
UPDATE: My "new" 233 unit arrived today! :mrgreen:
Actual unit weighs only 68lbs... much lighter than I expected.
![]()
![]()
I purchased the unit though Ebay, $175 (including shipping)
This unit is from an 03 Blazer. I confirmed it has 32-spline output.
![]()
I've read there may be some case indexing issues old vs new.. I'l let you know how this one does.
The unit is light enough it can be lifted and carried with one hand.
I turned everything by hand and verified the 4x4 Hi/Lo selector is working.
![]()
The new basic gasket/seal kit arrived today as well... $12 on Amazon.
![]()
Now to fabricate my manual shifter.
I'm learning toward possibly something similar to this that "LiftedAWDAstro" did on the other site... but perhaps either a little shorter, or further back.
I will experiment with leverage lengths and angles once the cable is in place.
I have a box that sits in the center between the seats, so this really won't be visible.
![]()
Looks like I may go with this Lokar S-7100 cable kit ($50 from Summit) connected to a simple shifter mounted to the side of the driver seat facing forward. I think I'd prefer the shifter close as possible to the seat vs cutting open the floor.
This cable kit appears to have everything I'll need (except actual shifter lever)
![]()
But I'll probably take a visit to the junk yard just to see my other options.
I'm pretty excited about taking this to the next level!
See more at NP233 vs NP236: https://www.astrosafari.com/viewtopic.p ... 9&t=135734
-------------------------------------------------------------
July 7, 2018:
The new unit is here.. I'm just shopping for my best linkage solution. Still undecided on the Jeep Liberty shifter (found a nice one in JY yesterday).. or making my own (shifter mounted on the side of the seat base). The Liberty shifter will be the simpler and cheaper choice, and comes complete with everything I'll need. I'm probably going to go back and pull it Monday, regardless. The cable though the floor to a simple seat mounted shifter is my preferred choice. But once I cut the big opening in the floor, the choice will be made.
I’ve been looking on eBay and having a hard time getting specific details on T-cases from junkyards (no pictures, no part #). My understanding is that there is some variation among 233C’s (spline count, flange vs. splined output to front driveshaft?) Can you advise me about how to avoid getting the wrong 233C?
I’m currently looking at one from a 2003 Blazer. It mentions NP1 (which is RPO code for 233C?) and that is has the 3-position electronic switch.
Here’s the link: 2003 S10 Blazer/Jimmy Transfer Case Assembly OEM 103K Miles (LKQ~239494368) | eBay
If the 3-position electronic switch is mentioned, does that mean it is the right one for a 2001 Astro? Thanks you in advance for any advice.
The later model Blazers all come with an electronic switch system.
The electronic switch system can be utilized if you pull all the components, switches, and wiring.
Most however convert the electronic system to a manually operated system, using levers and/or shifters and cables.
I don't know how far back the electronic 4x4 systems go in the Blazers.
You will want the t-case models with the correct 32 spline count, as shown in this chart (from post #21)
![Font Parallel Rectangle Number Circle]()
The electronic switch system can be utilized if you pull all the components, switches, and wiring.
Most however convert the electronic system to a manually operated system, using levers and/or shifters and cables.
I don't know how far back the electronic 4x4 systems go in the Blazers.
You will want the t-case models with the correct 32 spline count, as shown in this chart (from post #21)
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