How to wire up a NP 236 in place of a 136.

[racrx7]

SOOOOO, Has anyone else made this swap out work? Just curious

[Captn. Crunch]

I'll be taking another stab at it shortly. Also I find I have a neighbor with a big pile of parts who's also ready to take the plunge-right rinny?

[Snowgeek]

Still waiting to have the time to make it happen. Oil cooler lines and new pop top lift motors are screening to be addressed first.

R

[Snowgeek]

Still waiting to have the time to make it happen. Oil cooler lines and new pop top lift motors are screening to be addressed first.

R

[trip_south]

Grabbed a Blazer TCCM today, getting closer. I have a lot of splicing in my future as I've had to cut connectors off.
One question: I haven't been able to get a 4-pin connector to go into the transfer case for the encoder motor. Does the original NP-136 have a 4-pin connector that I can use (and just add the orange and tan wires to) with the 236, or is it solely a two wires (red and black) connector?
Thank you!

[Captn. Crunch]

Sorry dude but your gonna hafta find that plug. The 136 is a two wire and there's no getting around it

[trip_south]

Crawled under a blazer today to grab that 4 pin connector. Now I've got everything except the insulated butt splices and wire. What gauge wire is used? I see a couple thicker strands for the power/ground that maybe are 14 and then 16/18?
Also, is there a way to test the transfer case/tccm/ switch operation without installing it in the vehicle? I just mean using a 12v battery to test the encoder motor/switch operation.
Thank you!

[Astrophysics]

Yes. You should solder and crimp and prepare the harness first and use DMM, digital multimeter with continuity beep mode to "ohm out" the point to point wiring to make sure you have the correct From To anend wire colors. Also, wire up toggle switch to simulate shifting into neutral. Then get your test +12 VDC from a battery and make sure to put a 20 amp fuse in line to protect things.

Connect the TCCM switch, connect the TCase, apply 12volts, push the 4 Hi button and listen for the chunk noise from t case, repeat for 4 Lo, etc,
I bench tested a np231 t case this way.

AP

[trip_south]

Thanks for the info, I'll try to bench test it once I've finished all the splicing and rewiring. Any guesses on the wiring gauge? I see a lot of 0.35, 3, and 0.8 on the diagrams next to the wires...would that be mm2? And if so would that be 22, 18, and 12 gauge?

Second question:
Do you have any tips on repinning these connectors? Specifically, doing so without damaging the pins?

Third question:
What is the best way to do a three wire splice? Can you shove two wires in one end of a butt splice and crimp away?

Thanks!

P.S. I got my switch from a Tahoe/Suburban with NP246 case and vertical style switch. It's small connector has 4 wires and the larger one has 7 wires...it looks like everything going to the TCCM is identical and the other connections are similar too:
A BLK Ground to chassis (equivalent of the "G" wire earlier in the thread)
E PPL/WHT Body Control Module for LED brightness (equivalent to C2 "B")
F GRY Switch illumination (equivalent to "H")
G PNK 12 V with ignition in run (equivalent to C2 "C")

Hope that helps.

[Astrophysics]

You are making good progress. You may want to take a 2 'x 4' piece card board or plywood and make a so called "nail board" to lay out the harness as they do in electrical harness fabrication.
This takes a bit longer but forces you to be neat and accurate. Secure the multi conductor wiring runs and prep the splices. Don't forget to get some assorted sizes of shrink tubing. Slid a 1.5" or so length of shrink tubing onto the wire before solder joints. Then slid tubing over solder and use a match or hear dryer to shrink it for professional look. Instead of just black tape.
AP

[Snowgeek]

Well, it has now been a few months of having everything ready for this swap. I hoped to begin in November and have it ready for winter but I own a bike shop in Boise, ID and it was 60's and sunny through most of November and I had no time to think about it. Now it is winter and our local ski hill road requires that I have functioning AWD.... so spring it is.

I am continuing to study the diagrams and processes so that I am ready when the time comes.

In related news it has been quite the winter here this year and the Astro has been doing its community service pulling a hand full of folks out of snow banks..... I can't wait for low range!!

Ryan

[Snowgeek]

Well, it has now been a few months of having everything ready for this swap. I hoped to begin in November and have it ready for winter but I own a bike shop in Boise, ID and it was 60's and sunny through most of November and I had no time to think about it. Now it is winter and our local ski hill road requires that I have functioning AWD.... so spring it is.

I am continuing to study the diagrams and processes so that I am ready when the time comes.

In related news it has been quite the winter here this year and the Astro has been doing its community service pulling a hand full of folks out of snow banks..... I can't wait for low range!!

Ryan

[Snowgeek]

Well, it has now been a few months of having everything ready for this swap. I hoped to begin in November and have it ready for winter but I own a bike shop in Boise, ID and it was 60's and sunny through most of November and I had no time to think about it. Now it is winter and our local ski hill road requires that I have functioning AWD.... so spring it is.

I am continuing to study the diagrams and processes so that I am ready when the time comes.

In related news it has been quite the winter here this year and the Astro has been doing its community service pulling a hand full of folks out of snow banks..... I can't wait for low range!!

Ryan

[Astrophysics]

Hi,

Yes, we drove our AWD 2003 Astro to snow near Bear Valley CA this last weekend. The Astro does great with stock T case . I never have had time to install the np231. Maybe I will get a np236 with the nice option for 4 WD Auto.

AP

[trip_south]

Not sure if PMs are working so posting this on the thread.
I'm getting ready to try to start the NP236 conversion soon (next few months) and have been looking closer at the tutorial. I understand that in this example original 32 pin TCCM connector from the NP136 on the van was used and all of the wires for the 236 were added, enabling you to leave all of the speed sensor wiring in place. Looking at the speed sensor diagrams for 1999 Safari, 1999 Blazer, 2001 Blazer, and 2001 Tahoe there seems to be a discrepancy with the Rear Speed Sensor wiring. The High and Low connections are reversed in 1999 vs 2001. I included links to the wiring diagrams if you're interested.

1999 Safari (A-Low, B-High):
https://www.dropbox.com/s/dg0r0pp67ed6t ... d.gif?dl=0

1999 Blazer (A-Low, B-High):
https://www.dropbox.com/s/xx2jcsc5zqeu1 ... d.gif?dl=0

2001 Blazer (A-High, B-Low):
https://www.dropbox.com/s/wuvmsex40lm61 ... d.gif?dl=0

2001 Tahoe (A-High, B-Low):
https://www.dropbox.com/s/bkq9umz00vvn9 ... d.gif?dl=0

2003 Astro (A-High, B-Low)
https://www.dropbox.com/s/l4hhy6xdew5i5 ... d.gif?dl=0

I'm not sure what the consequences of reversing the speed sensors would be, I assume it would affect when 4HI was actuated. I will have to splice my van's speed sensors into the donor TCCM connector because I already have a harness with complete switch-TCCM wiring. Just want to make sure I wire it up correctly and was curious about what people thought of this.

Also, how do you access the Astro's TCCM? Do you have to remove the parking break pedal assembly?