Chevy & GMC Vans

Sharkfox wrote:Thanks for all the information guys.
I just bought an NP233 transfer case out of a 2000 Blazer and will be installing it with a manual shift lever in the next weekend or two. I think I have the shifter and linkage worked out but I am looking for some clarification on the wiring.
From what I can tell, you only plug in the VSS wire in the tailshaft of the transfer case. What do you do with the other connectors from the NP136? Did you end up pulling the fuse for the AWD under the hood?
I'm trying to cover all my bases ahead of time so the swap is relatively painless so any additional info would be greatly appreciated.

I zip-tied the other connectors up out of the way so they wouldn't get damaged.

Yes, I pulled the fuse. With it in-place, I had the "SERVICE AWD" light on and there was a relay in the dash that would cycle 4-5 times rapidly on startup, presumably trying to initialize or re-control the shift-motor that was no longer there. With it out, I have neither.

Pull the fuse. Got it. Sounds simple enough.
Ok. I see the connectors zip tied now. It looks like one has been connected then the wires cut. Is there any reason for that or am I safe just zip tying the unused connectors up and out of the way?

I'm also planning to do some sort of 4Lo switch but I'll have to get creative with the location. Under the van would never last a salty Minnesota winter.

Sharkfox wrote:Pull the fuse. Got it. Sounds simple enough.
Ok. I see the connectors zip tied now. It looks like one has been connected then the wires cut. Is there any reason for that or am I safe just zip tying the unused connectors up and out of the way?

Not sure I understand the question. Nothing was cut on my van harness. The three unused connectors were just gathered as much as possible and zip-tied to other plumbing. Dean had already spliced a pigtail for the remaining VSS connector, so all I had to do was plug my VSS connector into his pigtail. I recommend finding similar connectors and doing the same if you have any thoughts about "reversing" the swap at some point.

Sharkfox wrote: I'm also planning to do some sort of 4Lo switch but I'll have to get creative with the location. Under the van would never last a salty Minnesota winter.

I'm hearing that a lot. Makes me wonder if desert dust will be harder on my switch than I've guessed. They're cheap, so we'll see!

In the previous set of pictures I noticed this connector that looked like it had been plugged together and the wires cut off. Maybe it's just an optical illusion.
I guess I was just verifying that nothing had to be done like this.

The VSS on the 233 had a short cable with 2 ends on it. I grabbed that and used it as the splice piece between the stock harness and 233 VSS. It was just plug and play. No wires were cut. The pic is an illusion. The rest of the cables/connectors were zip tied to the harness. I also put some dielectric grease in them to prevent corrosion for the time when/if I ever went back to the 136 which I did after the winter was over and sold the van.

Herbie wrote:

Sharkfox wrote: I'm also planning to do some sort of 4Lo switch but I'll have to get creative with the location. Under the van would never last a salty Minnesota winter.

I'm hearing that a lot. Makes me wonder if desert dust will be harder on my switch than I've guessed. They're cheap, so we'll see!

I was concerned about that too when I did mine. I considered (and ran wires for) a dash mounted backup switch. The last two winters have been very dry here, so not much snow and wet. I have driven probably 1000 plus miles of very dust roads, no issues yet. Ideally, one would use a weather proof moment switch or mount it inside.

I know this topic is a lil old, but I have a question.
Why do you need to wire a low-range switch to the ECU?
Thanks for any info. Brad

[quote="LiveWire64"]I know this topic is a lil old, but I have a question.
Why do you need to wire a low-range switch to the ECU?
Thanks for any info. Brad[/quote]


By default, the ECU compares the signals from the VSS, etc. and will go into a limp mode if it detects the output speed doesn't match what it thinks it should be. If you're in low range, the drive speed is altered and the ECU will hold the transmission from going beyond 2nd gear.

With the low range signal into the ECU, it compensates and lets you use all gears.

And use a pin insertion tool to add the missing wire. (Connector 2, Terminal 16, for '01-'05 vans).

Ahhh, You answered a question about terminal 16 that's been on my mind. It actually does something when grounded. In all the Selectrac 4x4 setups, (Blazers, Suburban's, etc), Terminal 16, (connector2), of the ECU is connected to the TCCM and is sent a signal, (or ground), that 4LO has been activated. You just solved the last piece of the puzzle for my 236/246 swap. I was going to connect it anyways just to see if it would work.
THANKS!!

All you fellows in this thread have been very helpful to me in my venture of installing the 233c case in my 2000 awd . I have learned a few things to add to this thread that will hopefully continue to help others . I have been fortunate enough to have Mike Collins as a friend to help me out with this swap and invite me to his shop to use his lift . Thanks Mike for all your help . I will be adding this helpful info as soon as I organize all my pic's . We still have to engineer a shifter and ground out the t case to get 2nd 3rd and 4th when in 4 low. Hear are a few pics for now . Thanks again to all of you for all the info , you guy's rock .

Nice looking ride there Skullhead!! Now I know what mine will look like when its al done lol. Can I ask what size tires and differential ratios you are running? Oh, And how much lift? Thanks

Well I think I'll be joining the group. My $400 AWD van's 136 is shot. No AWD at all. Fuse ok, encoder motor ok...

I've got a 233 from a 98 Blazer, so I'm just going to toss that in. I don't have the vss pigtail though. Do you know if it's possible to use the vss from the 136 in the 233?

I'll probably tackle it around Christmas and take pictures...

Yes! Now that I am back from vacation I need to restart looking for an NP233. This thread is what made me decide to switch....thanks for all of the info as usual LiftedAWD.....I'm still kicking myself forw not driving out there when you 1st put it up for sale.

Hi All,
Looked at the np233C that I pulled from a 98 s10 blazer 2 door, zr2.
The clocking is wrong. On this np233c the front drive shaft is about 4.5" lower than the rear drive shaft. Wow, no wonder the cross member would need to be notched with this clocking. Maybe that was good in the short wheel base 2 door blazer? I don't want to notch cross member.
Back to pic part for one np233c from 2000 or 2001 blazer. With clocking similar to np136. The 136 in my 2003 AWD has the front drive shaft about 2" lower than the rear drive shaft.
As convenient as the np 236 sound with 4 auto, I read that the 236 case will wear thru from shaft rub unless the mod is done.

The np233c would also be easier to mod to get manual shift linkage from Jouneys Off Road.
I wish Jouneys would make an even fancier manual shifter with an extra cable and a pulley under neath to act as mechanical torque amplifier so that a shorter shift lever could be used inside by the driver seat.

AP

Hi All,

Np 136. T case in my 2003 AWD Astro. Clocking has the front drive shaft about 2" lower than rear drive shaft.

AP