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Hello from Poland , transfer case 233/236 questions.

237 Views 6 Replies 7 Participants Last post by  AstroWill
Hi Astro's drivers! Greetings from Poland. I plan to convert from AWD to 4x4 in my Astro 1999. Most often you recommend transfer case number 233C, while I bought 236CM. What is the difference between 233C and 236CM and will 236CM be suitable for converting from AWD to manual 4x4??? I also found this set:
will it be ok or can you recommend another seller? Thank you very much for your help, in my country it is not as popular a car and conversion as in your country. We love wildcamping and soft offroad , my Astro also often goes with humanitarian aid to Ukraine, such a drive will also be useful there more than the usual stock AWD I have now.
Thanks a lot for help !
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Welcome. I can not answer your question. Someone will be along shortly who can. If you tap the three dots next to your logo at the top of the page it opens an advance search window. Type in transfer case and read.
NP236 swap is great, I've done it and I like it. But its not the same as a NP233 swap which can be converted to full manual operation. The NP236 is completely electronically controlled just like the stock NP136 AWD case. It shares a lot of the same wiring but it requires a lot more wiring to be installed. The Journeys kit you linked will not work with a NP236. You'll need a new TCCM and a 4x4 selector switch and all the connectors for the new encoder motor.

Here's a write up on how to wire one up.
Yes it has been done, but is rare, with no long term reports on durability. It's just so much easier to use a 233. As far as "gaining" anything, you would only gain low range, because the AWD in 99 and up was so very good. Anyway, here are some links you can look at-

Glad you made it!
The NP236 is the ultimate fully electronic version (like the 136) but allows for both AWD and 4x4 (including low range). Being electronically controlled, it relies on sensors, controllers, encoder motors, switches, wiring, connectors, & power. It also utilizes internal clutches which can wear down. All these things can (and do) FAIL over time. This unit is quite a bit more involved to install... especially the wiring, switches, sensors, and controllers.

The 233C (with mechanical shifter mod) is completely manual.. no controllers, no sensors, no encoder motors, no switches, wiring or power... nothing to fail. It is chain driven internally, and completely manual. You simply pull your shifter and it works. It is EXTREMELY RELIABLE and easy to install.. bolts right on (even uses same driveshafts and yokes).. completely plug and play with ZERO wiring or electronics. I put a 233C in mine from a 2003 Blazer.

Either is a nice upgrade from the stock 136 AWD unit.
Bear in mind that the NP236 is ALSO AWD.. a mode the 233 does not do.
AWD is a better option for snow... since it automatically engages as needed.
Having selectable 4x4 (with low range) is the ultimate bonus setup.
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while I bought 236CM.
Not sure what the M is for.

No, I don't believe that you could manually shift the nv236 effectively, but there are instructions on how to use the 236 with our vans.
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