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np136 to np236

13K views 52 replies 18 participants last post by  joeg 
#1 ·
So I've been slowly but surely changing my van over from awd to 4x4. I love the awd in my 99 and didn't want to give it up switching to a manual two speed case. All research shows 136/236 identical other than lo range. I built my two speed by putting 236 guts in a136 case and adding the nv reluctor ring in the front case. I installed and used the 136 encoder motor to check awd operation. All works well. I have downloaded diagrams of the awd and 4x4 tccm plugs. All awd circuits are represented in the 4x4 plug. Now I need to build in the missing 4x4 circuits,swap tccm's and encoder motors. This is starting to look like it might just work
 
#2 ·
Holy smoke, Crunch, I'm impressed..... Not something I would ever try to duplicate, but I can't wait to see it done :rockon:
 
#3 ·
Thanks gavio
So far it's been a bolt on operation.The trick has been no down time for my DD. the wiring is the first real step into the unknown so it's really been fun so far. I'm just hoping when I'm done, it actually works!
 
#5 ·
Oh believe me-if this works you'll hear about it. When I googled np236 in a safari I found some who thought about it but backed away due the electronic mayhem. So it appears I'm the first to get this far. My thinking is that GM is lazy and is not gonna make unit specific items. They will underutilize 4x4 items for AWD. So far I've been right. The low range components fit inside the one speed case. The one speed encoder motor works the awd of the 236. The circuitry in the tccm plugs are identical pin wise. All I need is to document the pin to component wiring the rest has been direct replacement. No driveshaft issues no issues of any kind with fitment. So thanks for the vote of confidence and stay tuned. One way or another we're all gonna find out!
I do have one question tho. Where can I get wire that matches GM schematics. It would be nice to do but for sure I'm not gonna let it stop me!
 
#6 ·
Where can I get wire that matches GM schematics.
I get mine at pick and pull..... There's literally miles of it hiding under the dashboards of GM cars.... I don't always end up with exact matches, but usually close enough to keep track of what I'm doing... One time I pulled all the wire out from under the dash of a Blazer and couldn't believe how long the wire runs were - one whole bundle ran back and forth across the width of the car... The wiring running to the back of a cargo van is another easy grab for long color coded wires...
 
#7 ·
gavio said:
Where can I get wire that matches GM schematics.
I get mine at pick and pull..... There's literally miles of it hiding under the dashboards of GM cars....
I think that's a very good idea. It's hard to find wire in anything but solid colors from regular, new wire retail outlets. They're usually limited to a handful of colors. To buy something with a stripe typically is obscenely expensive and/or requires buying huge spools of it. Getting it from a U-pull, along with some connectors, fuse panels, tie downs etc. Thar-R-Smarte.

Lump
 
#10 ·
To the P&P we go. Thanks for the ideas and support. Leeanne if I can't find what I need you'll be hearing from me. I've got summer camp with the Boy Scouts all next week so nothings gonna get done between now and when I get back. A week of molding the leaders of tomorrow while I sit in a comfortable chair by the lake. Rank has its privileges :wave:
 
#12 ·
Speaking of wire, I have had good luck with Volvo's having quality 8 gauge wire for their electric fans. And...the yards don't charge me for it if I am buying something else.
 
#16 ·
Corsemoto said:
racrx7 said:
Just curious CC, why did you swap the 236 guts into the 136 case? Will the 236 not directly bolt up?
Thx,
Andre
The both use the same case and share most internals other than 2-speed parts.
There are two reasons I put the 236 guts in the 136 case. First of all, I wanted to make sure it would actually work. I didn't want to post something that I had not done and claim it would work. Also the 236 case was cracked. Didn't find out till I started cleaning it up prior to teardown. So I was" forced " to go the route I went. I was planning on a side by side comparison and interchangeability session while I had both cases open but the cracked front case on the 236 forced the installation of the NV ring as previously posted.
So yes I could have just bolted an np236 in but once again what fun would that be?
 
#19 ·
Vandiction said:
Update on how it's functioning?
Update: it's going well thanks for asking. The transfer case is still being underutilized as a single speed awd. I have all the diagrams to wire everything together. I need to get to a P&P and grab a chunk of GM harness. I am also gonna need to see what I'm going to need to build the TCCM plug. I've actually been grabbing some OT at work so my play time is suffering a little
 
#22 ·
What started out as a crazy thought in my head two or three years ago has come to see the light of day it appears. For those of you who have put up with my ramblings all this time I thank you. What looked like a long shot is turning out to be anything but. Congratulations to racrx7. You showed up with a van, a willingness to sift though all of the posts here and ask all the right questions. You did what I've been shooting for for awhile now and good job. Not gonna lie, I wish I had gotten mine to work first but hell we all get to benefit from racrx7's hard work and the addition of the np246 parts is just over the top stuff. A shout out to meggabuddys over on the zr2 site. He is hip deep in modding these clutched transfer cases and is doing four wheel smokeshows in his 600hp turbo'd zr2 blazer.
Hurry up with the wiring tutorial will ya. If I can't be first, seconds the next best thing! Once again good job
 
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