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fulltime to parttime transfer case

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by natman77, Aug 20, 2001.

  1. natman77

    natman77 Registered Member

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    What all is involved in changing a np203 from fulltime to parttime 4x4. I know the hubs have to be installed, but what do you need for the transfer case?
    thanks
     
  2. wheelin247

    wheelin247 1/2 ton status

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    that is a good wuestion i would like to know to becuase i have a full time t-case and i put the warn premium locking hubs but i wanna know what else i can do to stop that front drivshaft from spinning all the time ?...good question
     
  3. natman77

    natman77 Registered Member

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    Anybody know??? Any help would be great!!!
     
  4. Seventy4Blazer

    Seventy4Blazer 3/4 ton status

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    you have to remove the front output housing. takes a big socket. inch and an 1/8th or 1/16th. then you remove the parts the instructions the kit says to and replace them.
    put it all back together torque it all down and now you have 4h, 4L, 2h, and 2L. it works great. you can do it in the truck too. no need to remove the t case. there is a new output you can buy for like 300$ but you can buy just the kit for like 30 from 4wp
    Grant

    1974 Chevy Blazer Cheyanne. but it is on 33's now, with saggy old springs. i am in Yuma Arizona if ya got any parts for me.
     
  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Mile marker builds the best part time kits. There are 2 styles. The cheaper one has a set of tabs that replace the spider gears in the transfercase Diff. The other replaces the whole assembly and is stronger but about double the price (around $200). The kits come with installation instructions. You basicly have to remove the tail cone assembly. Sounds worse than it is.
    Now a word of caution. The 203 was designed to be lubricated by the chain slinging oil. once converted the chain no longer spins so the case does not lubricate properly. Every 200 or so miles you MUST put the case in LOC (hub unlocked) and drive it a couple miles. This will re oil everything and refill the resivior in the tail shaft that supplies oil to the tail shaft bearing pump. Failure to do so will cause the 203 to fail.
    Before you do the conversion find a steep hill put the truck in low full time and floor it. if you get a bang that's the chain slipping and it needs to be replaced. Can be done in the truck but it's a Pain in the butt.

    It's not my damn planet monkey boy!
    <a target="_blank" href=http://communities.msn.com/OffroadK5s>communities.msn.com/OffroadK5s</a>
    75 Jimmy, Dollar
    79 Chevy Blazer, Her's
    70 Chevy Burb
    Grim-Reaper
     
  6. mike reeh

    mike reeh 1/2 ton status

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    the np203 part time conversion is great. I havent installed one but It was done to my '77 K25 when I bought it.. 2LO is really cool w/o unlocking the hubs.. aside from that damn chain, the 203 is a great case, a heavy strong beast...

    mike
     
  7. Sparky

    Sparky 1/2 ton status

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    Out of all the mods I have done to my truck (cam, 4in lift, 33's, new int. stuff, stereo, etc. etc.) the best mod I have made is the part time 4x4 conversion. Its easy to do and increases the overall driveability a lot. The only down side is that you do have to lock it in 4x4 every 200 miles or so like they said. But the way I see it, that just gives me an excuse to use the 4 wheel drive every 200 miles or so. In my mind, its a must for any southern 203 truck. Spend the extra money and get the MM shaft kit and not the crown gear kit. The crown gear kit just wedges the diff. closed, and they get loose over time and stress and cause a loose driveline.


    Sparky

    When all else fails... Check the blinker fluid.
    78 K-5
     
  8. MOABDADC22

    MOABDADC22 1/2 ton status

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    Ijust helped my buddy do his 78 1/2 ton. It was a piece of cake. Just follow the instructions and you will be OK. You will need a 1 5/16" socket for the rear pinion nut. Use grease to hold the needle bearings in the shaft. When we were done, it would not shift into 4WD at all. The problem was that the linkage was dirty. A trip to the carwash fixed tah though.

    <a target="_blank" href=http://www.moabdadc22.alloffroad.com/>http://www.moabdadc22.alloffroad.com/</a>Real four wheelers don't need tools to remove body panels, paint, tail lights..etc.
     

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