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machining a TH400 adapter for mating to 4L80E

Discussion in 'The Garage' started by Leadfoot, Jun 16, 2005.

  1. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    I have the new style adapter and need it machined to fit the 4L80E case as well as the "spacer". I remember seeing a post on a company and/or member that performed the machining as well as sold the adapter but cannot find it. Does anyone know who can do the machining and or makes the adapter?

    Thanks.
     
  2. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Why would you need a spacer? I thought the only required mods to the '85+ TH400 adapter was machining a groove for an o-ring and then grinding on the mounting flange for clearance for some part on the tranny tail?

    I haven't seen any posts about a company doing the work. All of the posts I've read outlined the before mentioned mods. :dunno:
     
  3. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    I could be wrong, but I thought those that used the exact combo, either had to cut the 4L80 output shaft down or use a small spacer. If not, that would be great news for me as it would save me some coin.


    Anyone use a 4L80 with newer style NP205 and newer style TH400/NP205 adapter that can verify either way.... :confused:
     
  4. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    I guess the best way to find out is what the shaft stickout of the 4WD TH400 vs. the shaft stickout of the 4WD 4L80 is and compare. I have looked online but all of what I have seen give 2WD dimensions.
     
  5. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    The tailshaft "stickout" for an '85+ TH400 with a round pattern 205 = 2.25". I have one at home and checked this measurement previously for a post n the ORD forum. :thumb:
     
  6. sweetk30

    sweetk30 professional hooker Premium Member

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    like this one? if so its mine just ask me how.

    205 spacer.jpg
     
  7. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Thanks for the pic.
    That's an 84 and down 205 and adapter, but which input shaft did you use? Also what is the thickness from front to back of the adapter? I will have mine shortly and can compare. Knowing which shaft you used and differences (if any) in thickness fo the adapters, will let me know what I will need to do. Also, did you machine your own adapter? If so, are you interested in doing any more?
     
  8. sweetk30

    sweetk30 professional hooker Premium Member

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    4l80-e 2x4 fixed yoke tail. 1 1/4" thick 6061 aluminum spacer. friend made it for me cost total 125. only problems were as you can see is grind a bit off the webs to clear the longer bolts to hold to the tranny, if studs are used no need to do this. and other is major dont forget to change the plug at the 3 oclock position from the pin hole plug to a solid plug. this is for the oil to the bearing in the tail needed for fixed yoke. when going to 4x4 not needed and will cause loss of oil pressure on that circet in tranny. less than 5 bucks at dealer. if you need any more info just ask. possible to make more if needed.
     
  9. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    If you need any adapter measurements let me know, I have both styles at home.
     

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