np136 vs np236

[Captn. Crunch]

Well I just got off the phone with the guy who was gonna put me over the top with the wiring harness and PCM from a parted out S10. I guess he got happy with the dykes and it looks like I'm SOL on that one so back to Craig's list. Soooo close!!!

[AstroWill]

This seems like the best option as far a as a TC swap. I wouldn't want to get rid of the AWD either. Good work!

[Captn. Crunch]

Thanks astrowill I appreciate the support and I hope it all works out. Then I'll take the congratulations. Til then I'm just some guy throwing stuff under my truck and hoping it sticks [-o<

[AstroWill]

Well keep on throwing, hopefully it does stick and others can follow the path

[Captn. Crunch]

So I'm ready to start the task of accessing low range in my tc swap. Before I do I thought it would be only fair to offer you to help. If we were in charge of designing the 4x4 system how would we do it. The stock setup was a bit cluttered and had all kinds of little bits that would fail and keep the system from working. Lets see if we can't improve on things a little bit. Let me know what you think?

[photo_van]

Elimination of the TCCM and the shift motor. Put a lever on the 236, a hole in the floor, and a manual shift selector.

[AstroWill]

Well I just got off the phone with the guy who was gonna put me over the top with the wiring harness and PCM from a parted out S10. I guess he got happy with the dykes and it looks like I'm SOL on that one so back to Craig's list. Soooo close!!!

What years/models does it need to be from?

[Captn. Crunch]

Elimination of the TCCM and the shift motor. Put a lever on the 236, a hole in the floor, and a manual shift selector.

If I wasn't so set on keeping awd I probably would have gone that route. The 236 is the four button case with 2hi 4hi 4 lo and 4auto. The 4auto is exactly the same as the 99+ awd. I have to wire this case to the computer to keep that function. So I'm looking for parts from a 99+ s10 4x4.
pcmforless is pretty sure that I might be all set electronicly as GM doesn't like to do one off stuff so my ECM / PCM very well could be the same as the s10 and are under-utilized. I will be pulling covers tomorrow to check and will let you know

[photo_van]

I threw out this question somewhere here before; "do you/we think the 236 awd clutches would hold up to constant engagement"? Some thought that they would. I honestly have no idea, though I think if AWD was used sparingly i.e. only when you really need it, it would work well.

As I understand the way the 236 AWD system works is that when a speed differential is measured between the front and rear TC outputs, the TCCM asks the shift motor to shift to AWD. Other than shifting the TC to the AWD mode, the TCCM has no baring on the actual AWD system; the AWD system is mechanical by means of the internal clutch pack. By putting in a manual shift system, you could still have AWD, but it would be manually selected and would always be activated when selected. This could also eliminate the "lag" time people complain about in the 136.

If I had a '99 or up, I probably would have done that rather than the 242.

Also, it is said that the PCM's are the same as the s10. I wired my low range switch to the appropriate port (per s10) on the PCM and it worked.

[Captn. Crunch]

Your almost right. The 136-236-246 all share the same clutch pack. The 136 encoder motor is two pin and is on or off. It reads wheel slip and cranks in the clutch pack until wheel speeds match. The 236 has a four pin motor. When four wheel hi or low is selected the motor has an electric brake that holds the clutch pack in full lock mode with no slippage. The 136 motor isn't designed to hold and will burn out if you wire it to lock.
I have the two speed motor. I need the four pin plug and any other wiring I still haven't figured out exactly but it's not much.
So you tied into your existing PCM? That is one piece of info I haven't been able to nail down thank you!

[photo_van]

Interesting. That's basically what the 242 does, locks out the center differential for part-time 4wd. So can the clutch "lock" be activated by the throw of a mechanical arm instead of the shift motor?

[Captn. Crunch]

There are three detents that can be selected by hand. Low neutral and high. But there is additional rotation that's against the spring pressure in the clutch pack. I dont believe this tc is conducive to manual operation.

[photo_van]

That's good info! no detent for 2hi?

[Captn. Crunch]

Neutral would be 2 hi

#-o http://www.zr2usa.com/mboard/index.php? ... 040&page=1

This is a link to an np236 thread on the ZR2 site very informative. It gets real good when megabuddy wades in

[photo_van]

LOL, ya, best not to confuse neutral with 2hi or you won't get far!

Thanks for the link. After reading it all I think I might agree with the one guy that posted; "Honestly I would just install a np 242 HD would give you all wheel drive, 2hi, 4hi, 4lo "

Sounds like you might want to put your 136 clutch pack in the 236? Less 2wd drag?