KK 2WD to 4WD conversion

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jaytango

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I probably won't do it but I was curious about converting my 2WD KK to 4WD. From what I understand, the KK uses the MP3022 (Selectrac II) or MP1522 (Command-trac II) transfer case which, are electronically controlled. I've been researching the controls of the TC and on one service site it says that the TC receives pulse-width-modulated voltage to actuate the motor into the 4 various modes. There's a cool video on YouTube where the guy has an opened TC and he's controlling the forks with external voltage to demonstrate the different positions. The MP1522 seems like the better choice since it's simpler and has less electronic functions. If I could theoretically come up with a method to use the stock console switch (2WD, 4-hi, 4-lo) and McGuyver the specific voltages to the harness pins and use an inline momentary switch to supply the voltage (basically, I'd be the control module), I think this could be a fun project. I do moderate mechanic work (swap out cylinder heads is my most advanced job). If I can get the parts for cheap on ebay, I'm estimating $250 for front diff, $100 for 2 axles, $150 for front driveshaft, $200 for transfer case, $80 transm. tail housing, plus miscellaneous costs, I think I could keep it under $1K. How realistic does this sound? I know the consensus is sell the 2WD and buy a 4WD, but if it'll cost me under $1K and I do it in steps... Phase 1: Front diff and axles.... Phase 2: Transm. housing and transfer case.... Phase 3: electronics and final connection of front driveshaft, I think this would be a realistic and fun project. Any advice/suggestions?
 

tommudd

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Like many things, you maybe able to pull it off , but in reality would be much better to just sell it and buy a factory 4x4.
Plus then if you ever get ready to sell it you may run into other hurdles
But thats just me , I switched over 4 XJs and a MJ to 4 wheel drive back 20 years ago, BUT much less to do , very easy back then and easier to get around selling them
 

Dave

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Yeah, I agree with Tom. Too much electronic stuff these days and you will need to take into consideration the down-time when you won't be able to drive it.

Easier to sell it and get a 4x4 KK if that is your desire to have 4x4. There's so much good wheeling down in Florida I would not be there without a good 4x4. I've wheeled all over the Ocala National Forest many times in 4x4 meets, and that's only one place to wheel down in Florida not far from Orlando. There are many others.

But if you decide to do a switch, we will want a how-to thread and pics.

Dave
 

Myke

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Use a 231J and a cable shifter. Not sure where the speedo sensor on the KK is but if it's in the differential or trans this would work. You would need custom length shafts made.
 

jaytango

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Does anyone know what's the stock ratio for the KK 2WD rear differential? I'm shopping for parts and a guy who has the front end asked me which ratio do I need. I'm assuming it has to match my rear diff ratio?
 

Myke

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and a bunch of wiring.................
What wiring would be needed? The 231J doesn't need anything wired into it. It's manually actuated by the cable shifter. If the speedo sensor is on the rear axle you don't need to touch it. Nothing in the front diff.
 

Myke

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Does anyone know what's the stock ratio for the KK 2WD rear differential? I'm shopping for parts and a guy who has the front end asked me which ratio do I need. I'm assuming it has to match my rear diff ratio?
3.73 if it's the same as the kj
 

jaytango

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Use a 231J and a cable shifter. Not sure where the speedo sensor on the KK is but if it's in the differential or trans this would work. You would need custom length shafts made.

I already ordered the mp1522 (coming in today). I wasn't sure how the 231 would bolt on to the KK (plus the different shaft flanges) so I went with the stock TC. I'm gonna start designing the homemade switching circuit using a DPDT and a meter to give me a position based on the 5v feedback. If this route doesn't work out well, I might do what you mentioned and just get a shift lever from the KJ and mod it, so I can remove the TC motor and have the lever do the shifting.
 

Myke

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I already ordered the mp1522 (coming in today). I wasn't sure how the 231 would bolt on to the KK (plus the different shaft flanges) so I went with the stock TC. I'm gonna start designing the homemade switching circuit using a DPDT and a meter to give me a position based on the 5v feedback. If this route doesn't work out well, I might do what you mentioned and just get a shift lever from the KJ and mod it, so I can remove the TC motor and have the lever do the shifting.

If you're into electronic projects you could probably make a switching circuit with an arduino.

Also if the KK has the 42rle it's the same trans on the KJ.
 

jaytango

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If you're into electronic projects you could probably make a switching circuit with an arduino.

Also if the KK has the 42rle it's the same trans on the KJ.

I actually did think about that. I'm a web developer and got to play a little bit with an arduino at my last job. Going that route, I could probably use the stock console switch and use like a 555 timer chip to constantly monitor the sensor position pin output and control power, direction and cutoff via a small script.
 

Myke

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I actually did think about that. I'm a web developer and got to play a little bit with an arduino at my last job. Going that route, I could probably use the stock console switch and use like a 555 timer chip to constantly monitor the sensor position pin output and control power, direction and cutoff via a small script.
That would be awesome
 

tommudd

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Since not taking advice will sit back and watch.............................
Used to be plain simple to do things like that , not so much anymore
Had it pretty much figured out for a KJ owner but he didn't want to after he heard cost and time. He traded for a 4x4
 

jaytango

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Transfer Case Test Videos

I made 2 videos demonstrating how to shift the transfer case and how to detect transfer case position. I hope to document every step of the way. I don't know how long this whole process will take me... maybe 2 months.... maybe 2 years. but anyways. It'll be fun. I love this kind of stuff. Hope you enjoy the videos and maybe it can help others too.

https://www.youtube.com/watch?v=Ge8YZ1DomGs

https://www.youtube.com/watch?v=evZBppj2R0Q
 

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