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

[tanvanmanwithaplan]

Well, I just pulled the driveshaft and it still does it, so either something's wrong inside the transfer case that is independent of the front being connected or it's not the transfer case.

[MountainManJoe]

When the transfer case is in 4 lo it will not shift into 3rd.

Is the PCM getting its output speed signal from the transmission or the transfer case?

[tanvanmanwithaplan]

When the transfer case is in 4 lo it will not shift into 3rd.

Is the PCM getting its output speed signal from the transmission or the transfer case?

I am not sure on this, but I wanted to correct myself here. The transfer case is indeed shifting into 3 and 4 in 4lo, it just either wasn't doing it up on jacks stands or I couldn't tell. I just drove up a hill in 4lo and counted it shifting three separate times. It goes about 30mph in 4lo at pretty high RPMs. On my van the shift from 1st to second is pretty hard, which is not the case in 2hi.

[tanvanmanwithaplan]

Update: my lower control arm bolts were very loose. I am not sure what caused this to flare up at that time but that is what was causing the noises. The transfer case is fine after all, I put another 500 miles on it this past weekend including some 4lo 4hi and lots of gravel all is well.

[Snowgeek]

Interesting. Any theories why the TC blew up?

How useful is 3rd when you're wheeling around in 4-low? At that speed, doesn't it make more sense to be in 4-high in 1st or 2nd?

I agree with Herbie, when I get to dirt with much grade at all I swap to 4 low and move on. With my stock gearing I can do 40 mph in 4low at 3300 RPM. This is nice in order to keep from swapping in and out of 4 low.


As to the transfer case binding up I will start spinning my brain on what is going on. I hope I can add something to this conversation!

Ryan

[Snowgeek]

Update: my lower control arm bolts were very loose. I am not sure what caused this to flare up at that time but that is what was causing the noises. The transfer case is fine after all, I put another 500 miles on it this past weekend including some 4lo 4hi and lots of gravel all is well.

Glad I could join the conversation once you have already found the issue

Glad you figured it out!

Ryan

[MountainManJoe]

So since you end up leaving it in low range most of the time anyway, then isn't it better just to use a manual shift TC, and not have to worry about electronics and failing shift motors. They're much cheaper too.

[tanvanmanwithaplan]

So since you end up leaving it in low range most of the time anyway, then isn't it better just to use a manual shift TC, and not have to worry about electronics and failing shift motors. They're much cheaper too.

I don't think the encoder motor is particularly prone to failing. People say it is a lot but they are also people who don't have them. The encoder motor on my 136 still worked fine when I pulled it at 170k miles and 20 years old.

The advantage of this approach is twofold: retaining AWD functionality and not taking up room on your floor for a floor shifter.

I paid $200 for my NP236 so I'm not sure the Np233 is much cheaper. But the journey manual linkage kit is $250 iirc. I did this project with the $200 transfer case, junkyard TCCM and switch and pretty much everything else I had on hand.

That said: if you do not understand wiring and electrical systems I would not tackle this project. I would also consider this to still be closer to experimental than the 233 journey linkage swap.

[MountainManJoe]

I guess I can't relate. My Astro shift motor died. Maybe around 120k.
NVG136/236 are not true AWD either. It's part-time.
Units like the pre-99 BW4472 are AWD all the time (and no electronics), and work better IMO.
My 136 always reacted too late.

[Herbie]

Manual shift TC makes more sense if you don't have the clutch controlled AWD as an option, but if the NP236 swap had been this well documented when I'd been doing my conversion so many years ago, I'd probably have taken that route.

[tanvanmanwithaplan]

Manual shift TC makes more sense if you don't have the clutch controlled AWD as an option, but if the NP236 swap had been this well documented when I'd been doing my conversion so many years ago, I'd probably have taken that route.

I would also consider electronic 3 button swap... Encoder motors are easy to replace and cheaper than the linkage kit in either case if it does fail.

Nearly every 4wd vehicle made in the 21st century uses encoder motors. But hey if you want a lever more power to ya. If I had a linkage set up already I would just keep on using it.

[MountainManJoe]

If you don’t handle a lever like a gorilla, it shouldn’t break

[tanvanmanwithaplan]

If you don’t handle a lever like a gorilla, it shouldn’t break

That is not what I was getting at--I am saying replacing a 20 year old encoder motor once should it break is less work and less expensive than the kit to add linkage from Journeys off road.

I would say this is quite off topic for this thread at this point though. There are plenty of threads on the linkage swap, which is also quite capable vs the stock AWD setup.

[tanvanmanwithaplan]

The NP236 switch has a red LED for neutral, but I haven't been able to figure out a way to put the transfer case in neutral. What is this light for? Does anyone know?

[Snowgeek]

@ Mountainman - I do not drive my van in 4low most of the time. But if I am out in the mountains on dirt roads that will require 4low at times I will leave it there and let the van shift as needed until I hit pavement or speeds that don't make sense. This would be the same as wheeling in my 1991 Toyota 4runner (RIP) put it in 4 low and then use the manual transmission in gears 1-5 until once again I hit pavement or need to go faster than 5th comfortably allowed me to go.

Regarding the 236 vs 231 or 233.... different cases are right for different people. If i was only dealing with pavement and dirt I would have gone with a manual t-case and not looked back. The cost of the 4x4 conversions here are so low either way that debating over a couple hundred dollars makes no difference to me. However, I drive on snow.... a lot...... and the 136 dose this very very well. I was unwilling to give that up just to have 4low so the 236 case is right for me same awd and 4low to boot. The encoder motor could go out and on a blazer it can be a beast to remove..... on our vans it is very easy to swap. When I started this project I bought 2 of every electronic part at my local pick n pull in order to be able to track potential problems of used parts and also to have as spares down the road. The spare TCCM, encoder motor, and switch set me back $45 bucks if i remember right. As far as the engagement of the 136 or the 236 I can't think of a time where I noticed it engage late. I am on snowy roads all winter long.... my ski area is 16 miles with 40-50 20mph turns 1/2 of which are typically some version of snow, ice, or water over ice. In these conditions the van tracks substantially better in AWD than it does in 4hi. I would like the simplicity of stiring the case with a shift lever but i will accept the wiring and the electronic gizmos to have my snow traction along side my 4low.

- To date since installation my 4x4 has been 100% ...... it has never missed a beat. I still carry extra parts for this system on certain trips but haven't had to use any to date.

@Tanman - You can put these in neutral, but it is not obvious. Here is a video showing the the switch that I am using for my rig, pressing 2hi and 4low button at the same time for 10-15 seconds. I have never found a use for this but if I had a situation where I needed to flat tow my rig it could be useful.

Snowgeek