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NP 205 yoke conversion question?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by JK5, Mar 18, 2002.

  1. JK5

    JK5 1/2 ton status GMOTM Winner

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    Has anyone converted there NP 205 Slip-yoke into a fixed-yoke? Is it difficult, can it be done with the t-case in the truck? I need some input/info!!!!!
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    My friend is talking about the same thing. His idea, I think I have this right, is to drill and tap the output shaft, since they are (almost?) always at least "dimpled" for a bolt.

    I'm not quite sure what he's going to do about the slip yoke portion on the driveshaft though...
     
  3. DPI

    DPI 1/2 ton status

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    It is a very simple conversion. Just un-bolt both rear output housings and exchange the two. There are some loose needle bearings, so be careful when you pull the output shafts out, the bearings may drop into the bottom of the case. Mine did, but I was able to retrieve them with the aid of a magnet.
     
  4. BILLY RAY

    BILLY RAY 1/2 ton status

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    VERY EASY JOB
    JUST CALL STEVE AT O.R.D. HE HAS ALL THE PARTS YOU NEED.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Witht he slip yoke 205, isn't the output shaft longer than the non-slip yoke? Provided he did have a non slip yoke 205 parts donor around, is unbolting the output housing the only thing needed to swap all the pieces?
     
  6. DPI

    DPI 1/2 ton status

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    That is basically it. There are like 10 bolts or so holding the output shaft housing on. I had a donor case so both were side by side. The slip yoke housing came of without the shaft, then you just carefully pull out the shaft(watching for falling needle bearings). The fixed yoke housing came out with the shaft. I don't remember if the shafts were different lengths. You will need a new shaft, so I was not worried about that.
    This is really very simple and shouldn't take more than an hour for a mechanically oriented person.
     
  7. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Go to my CK5 member section (using the link below). I have pics of a rebuild including pictures of the differences between the slip and fixed yoke parts. There is no text yet. I am giving the descriptions ot Steve with the teardown and rebuild info for him to put in the tech section. I just have to find the time to do it. I just about had the time to do the rebuild and yoke conversion (I also converted to the Ford 32 spline front output while I was at it). Swapping the slip yoke out for a fixed yoke is easy if you have the whole rear section (output shaft gear, output housing, bearing/seal retainer, and yoke) of the donor case. They you just pull the slip yoke rear housing out (collect the fallen needle bearings) and then pack the bearings with grease, install them in the fixed yoke assy. and bolt on. you may want to replace seals and gaskets at this time which requires a little teardown, but overal it's an easy mod that can be done in the truck (keep an extendable magnet handy to pull the 15 needle bearings out of the case as they fall in which is the most technical part). On other thing I noticed is some housing use the old push in speedo assy, and some have the screw in style, and some clock the speedo to the driver and some to the passengers side, which may necesitate re-routing the cable.


    update: Here is a qucker way to get there as it's not intuitive
    http://coloradok5.com/gallery/albun75

    update2: More pictues will be added when I give the review to
    Steve, and sorry for the quality. My first time with a digital camera.
     
  8. JK5

    JK5 1/2 ton status GMOTM Winner

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    I have a doner output housing/yoke, I called ORD, they are sending the gaskets I need !!! Thanks for all your help and pics!!
     
  9. Jay73K20

    Jay73K20 Registered Member

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    Why would you want to do the conversion. I personally have a fix yoke but my buddy has a slip yoke and I see nothing wrong with it. Benefits of a slip yoke is, easier to correct your speedometer and you can make a cheaper and stronger drive shaft. I was told by drive shaft shops that the slop in the slip yoke on a fix yoke drive shaft makes it weaker and less stable then a slip yoke output. I’m sure that is why GM engineers changed our trucks to the slip yoke output in the late seventies. The benefits I could see with a fixed yoke would be that if you had a divorce transfer case and had the same length front drive shaft as a rear drive shaft so you could interchange them. Unless you have a blazer or short bed with to much lift and you need the extra length to decrease the U joint angles. Just my opinion.
     
  10. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Well in a non lifted vehicle the slip yoke is not a bad design and fairly strong (the longer the shaft, usually the weaker it is, and the slip yoke is longer). When you lift a vehicle the angle of the shaft puts undo pressure on the slip yoke. The movement of the driveshaft is vertical but the slip has to occure in a horizontal plane (not good, more angle the worse it is). A fixed yoke with the slip in the shaft compensates by allow the slip in a dual plane (vertical and horizontal). This creates less stress on the joint. Also when operated at extreme angles and droop, the slip splines tend to wear much quicker on the slip yoke and vibrations are a bigger problem because of the above metioned problems. Again, it's not a bad design for a stock vehicle with stock ride-heights and drive-angles, but for lifted and driveline taxed vehicles a fixed yoke is better.
     
  11. JK5

    JK5 1/2 ton status GMOTM Winner

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    Have you ever lost your rear driveshaft, I know I have, It sucks getting under the truck with a modified pop can to stop the fluid from coming out!!! Maybe I don`t want any vibs, with a 6 in. lift on a Blazer!!!
     
  12. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    That too! Almost forgot about that /forums/images/icons/blush.gif.
     

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