NP233 electric shift to manual shift swap

[LiftedAWDAstro]

Well I can only say it works great...I have only driven about 3 miles so far. The transfer case has synchronizers so yeah, you can shift on the fly. Just like any other transfer case, make sure you aren't spinning when shifting. I had to make a small adjustment to the cable at the t-case end due to it not wanting to disengage completely. Just needed an 1/8" adjustment.

I also was wrong earlier when I said it was slightly shorter than the 136. They are about the same length. I had the van in the air and the axle was hanging. Once on the ground the slip yoke goes in as far as it did.

[Stroverlander]

Awesome!

[Smiliesafari]

Very cool, Dean. I was a little concerned about the driveshaft. Glad that worked out.

[LiftedAWDAstro]

Got to use 4x4 last night after snowshoe running. It was snowing pretty good and the roads were covered. It engaged and disengaged fine. I do get a slight bit of bind when going from 4x4 to 2WD. If I let off completely it will disengage. On wet roads it stays in 4x4 until I let off completely. I think this is due to the 4.11's out back and 4.10's up front.

Today I used 4LO while plowing snow and it is nice being able to creep along without stressing the tranny!

[thegreenmachine]

this is my next mod. and axle swap. gonna need help with the linkage though.

good job, looks awesome. I am "green" with envy!!!

[chuck.z]

Hey Lifted, curious if the 233 has the shimmy on snowy conditions like the 231. In the other thread discussing the issue, TLow believes that his setup doesn't have the shimmy because of the 233. Can you post on your experiences?

[LiftedAWDAstro]

I don't know for sure as my 233 was not installed and run in too much snow. Plus my 2005 was stock height with basic all season tires. I would have given it a workout this year but not last year. I don't recall it pulling at all.

[Herbie]

Well, as the new owner of this particular transfer case, I guess it's my job to post an update. We've had our first rain here in months, so I was delayed getting photos, but I didn't want to violate rule 6.b, so here we go: (My full album of photos is here.)

The completeness of the work Dean did means there's very little new "art" here.


Transfer case and eBay replacement front driveshaft (to cure my clunk/knock/click issue) bolt in without modification. Nice.



Guy who helped me install the case was pretty nervous about not reconnecting all these sensors. Told him to "trust me".



Should I be concerned about the "clean spot" on the rear driveshaft? This is with the van on its wheels. Is it too short or is it just clean from compression under load?



Here's my one "new" bit, a bracket to mount a microswitch to tell the ECU when I'm in 4Lo.



And after adjustment and painting.


It'll mount here under the shift-cable bracket and close when the selector lever is pulled 100%.



Like so.



I fretted this whole shift linkage for WAAAY too long. Dean had it all figured out.



A single hole in the floor takes the cable up to the cabin.


Oddly enough, the best tool for tightening this end of the linkage ended up being my small basin wrench. A crow's foot wrench would have worked too...



In the cabin, just a single, tidy hole. Still looking for a nice plate to top this off. The rubber bush at floor level should be just right to trap something decorative there.



Connect to the shift lever, and I'm mechanically done.



Next comes the electrical. I haven't seen much of this, so I'll try to describe: Disconnect the battery. Unlock the ECU.



Remove the appropriate connector. In my case, C2 is the "Green" block (versus the Blue block). Carefully remove the plastic cover on the back of the plug to expose the insertion end.



And use a pin insertion tool to add the missing wire. (Connector 2, Terminal 16, for '01-'05 vans). There's an orange rubber "gasket" that fills the hole for the pin. You can use the insertion tool to just push the new terminal right past this.



You can just make out the insertion tool in the block. Remove the tool and tug on the wire to make sure the terminal is seated.



I didn't have any un-crimped connectors of the right size, so I just harvested a short lead from this DB25 cable adapter. (The white block on the right was originally the inside portion of a CAT5 connector)



Then I soldered this little lead to the end of the hookup wire I ran from the switch end of things. I ran the wire along the same run I used for the #2 jumper cables I used to connect the house battery, since they followed a convenient path. Right about now is when my wife came home. Always makes her nervous to see my soldering iron sitting in an engine bay... After testing that the switch correctly grounded the pin at the terminal block, I re-inserted the connector to the ECU (observing the warnings about not over-torquing that bolt!). Unfortunately, haven't actually tested 4-Lo shift behavior yet! Need to do that this weekend...

Last step will be to apply the Z71/4x4 stickers on the rear quarters of the van. Need to wait for better weather, though.

[photo_van]

nice job on the micro switch! I wouldn't worry too much about the driveshaft; mine has a lot more shiny then that and hasn't fallen off... yet Also; what year and model vehicle was your t-case?

[Herbie]

nice job on the micro switch! I wouldn't worry too much about the driveshaft; mine has a lot more shiny then that and hasn't fallen off... yet Also; what year and model vehicle was your t-case?

Thanks! According to Dean upthread, it's from a 2000 Blazer LS 2 door.

[Stroverlander]

Nice work! It's always great to see photos of the process, especially the electrical. Looking forward to reading about how it works for you.

[LiftedAWDAstro]

Excellent install! I do like the addition of the low range switch. That would never last around here due to the massive amount of salt we use on the roads. Plus I didn't need low range for any more than plowing snow so 1st gear was enough for me. I wouldn't worry about the shiny portion on the rear driveshaft. That will slide in/out as you wheel it. Unless the rear axle falls completely off the van, it'll never slide out. Nice thing with the NP233 t-case is you can use basic tranny fluid! No Auto Trac 2 needed.

[Herbie]

Nice thing with the NP233 t-case is you can use basic tranny fluid! No Auto Trac 2 needed.

Oops. I used the AT2 (already on hand). Any problem with it, or just wasted a bit of money?

Need to add once more: Thanks again for all the great work! I was always going to swap in a new T case, but you sure made it easy. ;-)

[LiftedAWDAstro]

I don't think there will be any issue using it, just extra cost. You are more than welcome! Thanks again for purchasing the setup off me!

[Sharkfox]

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.