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NP-203 part time kit - Output feels rotationally sloppy...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BorregoK5, May 5, 2002.

  1. BorregoK5

    BorregoK5 1/2 ton status

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    With my rear driveshaft off the other day I found that the rear t-case output has about 1/4 turn of rotational slop. Side to side and up and down are nice and snug. Since I bought the truck with the part-time kit already installed, I'm unsure of just how much slop is normal and the clunk it makes when going into drive or reverse is a concern. The axle pinion has a bit of slop but only about 1/3 of the t-case slop. I'm worried that this much play could be a sign of wear and contribute to u-joint failure. Any opinions?
     
  2. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    I just bought a 78 K10 a few months back with the same problem (tight up, down, side to side, etc) and causes a clunk when going forward to reverse. I have been told (TIFWIW) that there were two kits available to turn the 203 to part time. One was cheaper and used aluminum "tangs" to lock the internal differential and worked well for the street but eventually starts to wear, and the other kit is more expensive which uses a new output shaft (that gets rid of the differential) and will take considerable abuse (not indestructable though). This is all "hearsay" as I have yet to pull one apart to see.
    I have a feeling you and I both got a 203 with the cheap kit installed. I am going to get the more expensive shaft upgrade and see if that works. I know the u-joints and pinion are tight but that slop in the t-case puts undo stress on the rest of the driveline so I would like to fix it as soon as possible.
     
  3. BorregoK5

    BorregoK5 1/2 ton status

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    That was what I was afraid of. Well, i'll pull mine apart here in the next day or so and post what I find. Do you remember the maker of the good kit or a location to purchase it?
     
  4. BorregoK5

    BorregoK5 1/2 ton status

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  5. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It's normal. It's not the part time kit were your getting the slop as long as you have the correct end play (in out about two thousandths). It's everything in front of it cumulative. There is some slop in the reduction box, some in the planetary gears in the tranny and some in the parking paw in the tranny.
     
  6. BozoWise

    BozoWise 1/2 ton status

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    So guys would you rather do the shaft conversion or change the case to a 205. I can get a 205 for about the same price as the conversion kit for my 203, but which one do you guys feel is the stronger setup?
     
  7. HarryH3

    HarryH3 1 ton status Author

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    The 203 is pretty strong, but the chain needs to be replaced occasionally. To switch to a 205 would require that you also alter the length of both driveshafts, so don't forget to add that into your cost equation.
     
  8. BorregoK5

    BorregoK5 1/2 ton status

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    Grim- I'd expect some slop, but not a full 1/4 turn of unresisted movement. It's making for a huge bang going between gears.

    As far as the np205 vs np203, I haven't ruled one out. Not as a replacement mind you but since I already have a 203, a doubler comes to mind. A direct swap would involve more than just the t-case as the np203 is about 22 inches long and the np205 is about 12 inches long. This means your driveshafts would have to be reworked, and unless you found a fixed yolk version of the np205, they would have to be completely replaced. I'm not sure about crossmember clearance for the front driveshaft, that might stay the same.
     
  9. BorregoK5

    BorregoK5 1/2 ton status

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    Hey Harry, Have you or anyone else run the Mile Marker chain tensioner kit as you don't have to replace the chain? I had never heard of it until looking into the part-time kits.
     
  10. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Both mine are about the same. My 75 did it worse before the part time kit (the bang). Your going through a lot of gears between the parking paw and the tail shaft. It adds up. THe 205 is not going to be much better. As long as the tail shaft end play is right forget about it. I would stick with the 203 till you get the parts together for the doubler. If you go to the 205 then both shafts will have to be modified. If you wait till you got the parts together then thee is a really good chacne you would only need to redo the front shaft. Stephen says the Gen II kits the rear fixed output is about the same location as the stock 203.
     

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