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Mating a 4l80 to a NP205

Discussion in 'OffRoad Design' started by Leadfoot, Mar 13, 2002.

  1. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    My new rig currently has a (swapped in by previous owner) 350 (27 spline) mated to a 205 and I want to someday put in a 4l80. Advanced adapters offers a kit, but I was wondering if you do and how it mates (i.e. what needs to be done). Thanks
     
  2. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    I would treat the 4L80 basically as a TH400, you'd want to have a 32 spline input gear in the 205 and then the correct adapter to bolt the two together. Basically we tend to start with factory parts to put this stuff together where advance starts with custom built parts. That's the major difference. With factory type stuff my may spend almost as much but it's typically easier to replace if broken and should be worth more if you try to change it later. We also tend to look at future mods as our customer's rigs progress and can usually help you avoid steps backwards.
     
  3. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Thank you!

    Edit----> But another quick question. Is the shaft stickout the same on the 4l80 as the 400 or will I have to get a custom output shaft?
     
  4. ccj8008

    ccj8008 1/2 ton status

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    I have a 91 crew cab dually 4x4. It came factory equipped with a 4L80E and NP205. I am looking to mount a second T/case (divorced NP205) so I am considering swapping my mated 205 for another Tcase that has a driver's side drop. What is the stoutest case that I can get that will bolt up? Maybe we can work a trade. Email clayjephson@hotmail.com.
     
  5. Sledge

    Sledge Registered Member

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    ccj8008,

    If you do decide to ditch your current t-case setup, I'm interested. Depends on price and if Leadfoot wants it or not, of course. One of these days I really wanna get that 4L80E outta my garage and into my '72! /forums/images/icons/smile.gif

    Sledge
     
  6. u2slow

    u2slow 1/2 ton status

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    The BW4401 is probably the best bet for a tough LH drop t-case that mates to the 4L80E - fixed yoke too! I've had a couple fo NP241's apart and they did not impress me at all, and they're slip-yoke. I've looked into the same possibility (Dodge remote 205) on my '91 V3500. I have a 4401 that needs repair. I'm going to see if I can gut the front drive and chain when I rebuild it.

    On fitting the 4L80E to a NP205... This adapter is essentially a TH400/NP205 one, but the lip that extends into the back of the tranny is a slightly smaller diameter (<1/16"). This TH400 adapter was modified by a friend of mine (you can't even tell) to mate a 4L80e and NP205.
    <a target="_blank" href=http://209.53.37.213/~u2slow/tcase/adapters/th400np205.jpg>http://209.53.37.213/~u2slow/tcase/adapters/th400np205.jpg</a>
     
  7. Stephen

    Stephen 1/2 ton status Moderator Vendor

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    I think you'll be dealing with the 2.5" stickout shaft in the 4L80, there are ways of getting around that without messing with the trans. Basically you need a long 205 input gear to work with the 2.5" shaft.
     
  8. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Thanks. I think I have a lead on a 400 6 bolt version of the 205 and I will look for a long input shaft if it has the short. I will also need a 400-205 adaptor (6 bolt version) which should be fairly easy to find. Even with all this it should be much cheaper than the kit available from AA and gives me a reason to go through the case to see the internal condition
    Thanks again for all the input/help.
     
  9. DieselDan

    DieselDan 1/2 ton status

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    When you say "six bolt" are you referring to the "figure 8" pattern or the "circular" pattern NP205. My memory's not sharp enough to remember how many bolts I have under my truck.
     
  10. rocnwilly

    rocnwilly 1/2 ton status

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    leadfoot,
    I have a 205 with the round six bolt pattern long 32 spline input gear and the adapter to go with it. I bought it to mate to a Klune-v and have since decided to go with the doubler due to budget and I have purchased an 8 bolt 205 for my doubler. Interested? Oh, nice pictures and thanks for the 700r4 lock up diagram. Do you have a write up to go with it.
     

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