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stupid idea for mating a 4l80e to a np205?

Discussion in 'The Garage' started by mike reeh, Jul 19, 2005.

  1. mike reeh

    mike reeh 1/2 ton status

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    I have a 700r4+np205 in my truck right now... I want to get rid of hte 700r4 pretty soon but keep the np205..

    who here runs a 4l80e+np205? I have a 2wd 4l80e and was thinking of spending the $$ on making the setup divorced, rather than buying the necessary adapters.. what do you think of that? just throwing some ideas around in my head and wondering what you guys think...

    mike
     
  2. thatK30guy

    thatK30guy 1 ton status Premium Member

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    Be easier to get a new input shaft and machine the case to fit the larger bearing and then find the adaptor to mate it to the 4L80E instead.

    This was a factory setup for only one year. 1991 was the year and in all the 1 ton trucks of the "V" configuration.
     
  3. sweetk30

    sweetk30 professional hooker Premium Member

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    get 400 parts for 205 with adaptor. then go to dealer and get 4x4 oil pug for the tranny . this is at the 3 oclock position on the tranny when tail housing is off. fixed yoke is pin hole in it to supply oil to the bearing in housing. 4x4 dont need it so it is solid plug. if not changed will burn up tranny. plug is 5.00 or less. then have friend or you make spacer out of (i used aluminum 6061 ) material. needs to be 1 1/4" thick for fixed yoke to 205 with figure 8 adaptor. this spacer will look like 700 to 350 spacer. but the oring lip is diffrent size on 4l80-e. so make note of it when making adaptor. other than that this will severly help front shaft to tranny pan clearnce problem.



    p.s. hear is a pic for ya:p:

    205 spacer.jpg
     
  4. mike reeh

    mike reeh 1/2 ton status

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    well i became a member so I could see the pic :) been a while since i started this thread..

    sweetk30- is that a pic of your setup? Did you have the adapter made?

    whilst looking a little more closely @ my 4l80e, its fixed yoke, I was expecting to find a slip yoke.. this makes me think a little MORE about running the setup divorced... But Im still leaning toward swapping the shaft out in the trans..

    as for the transfercase side of things, im not too worried. I can find/trade/steal the parts to convert to th400 style, or whatever it takes.. its making the 4l80e WORK first of all, w/o all the factory harness & computer.. I do have the entire setup from this '91 suburban.. Im wondering if the computer will run the trans in closed loop w/ just VSS and TPS... THEN I have to make vss & tps work on this old '77 truck.... these are my main problems so far... but I think I can get it all figgered out if I put forth the effort... Im going to look into the DIY-EFI site, and pick some of those guys' brains on getting the trans to run.. Im *not* paying many hundreds of dollars for an aftermarket box to control the trans.. thats the only thing I refuse to do when it comes to getting this setup working.... I remember seeing something on CK5 a while back about getting a np205 to use an electronic VSS sensor, im sure that will come in handy.. any other suggestions or input from you guys?

    mike
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    If you've got the entire 4L80E/TBI setup (am I reading that right?) why not just convert it all over? All those types of swaps have been done, so you know it's possible, and the benefits of TBI over carb are pretty much appreciated by all that have had both, so it just seems that would be the logical course of action...install it as designed, and work out the install problems, instead of trying to come up with a standalone trans controller from a stock application.

    Here's the thread about the "standalone" 4L80E controller.
     
  6. sweetk30

    sweetk30 professional hooker Premium Member

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    dont swap shaft easy to make spacer. can get one made for ya or get specs for ya. and new shaft over 160 range. i hade spacer made for 120 . and diffrent size lip for 400 than 4l80-e at addaptor seal area. this spacer takes care of that. and lot less time and work with just bolting up spacer than swaping shaft. and try this for stand alone wire harness for tbi and 4l80-e controll . cost is 400. bucks. good luck and just ask for any info.http://www.howell-efi.com/wk_tbi_index.html

    p.s. the tranny dont even care if it has tcase behind it to work correctly with computer. just run it as 2x4 setup and only problem will be speedo off in 4 low. big deal.
     
  7. dyeager535

    dyeager535 1 ton status Premium Member

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    I priced a 4wd output shaft a few months back and came up with about $70.

    Not counter to what you said, as the work to swap that is going to be great.
     
  8. Russell

    Russell LB7 Tahoe Status Premium Member GMOTM Winner

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    His problem is that he has a 2wd 4l80e with a fixed yolk. I'd just run divorced. Far easier, and probally cheaper once all is said and done :) I got a divorced case for 225 bucks shipped to my door, only other cost involved is making a bracket to mount the case, making the shift linkage, and having driveshafts made.

    Also, I dunno if you have your 77's engine built up or not, if it is fairly stock, why not swap the TBI onto it? Or just swap the whole newer engine in?

    That'd make shifting the tranny almost too easy!
     
  9. sweetk30

    sweetk30 professional hooker Premium Member

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    where for the price? mine was dealer item. but like we say to much work for shaft swap. and to much can go wrong with good tranny when all apart like that.
     
  10. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    It would be easier if you were going to run a Doubler:



    [​IMG]


    That's a 4L80E (4wd version) dumping through an NP241 adapter and into the 203 of the Doubler.....pretty slick and simple.

    I ended up ditching the whole 4L80E idea out of necessity when I went with the Mog axles (OD wasn't high enough)....but conceptually it was working well.

    Overall length is probably the single biggest obstacle.....oh yes, and the price to convert the 4L80E to a standalone compy.


    :laugh:
     
  11. mike reeh

    mike reeh 1/2 ton status

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    welp i dug this thread up, its a few months old.. heres what i decided upon:

    leaving the 4l80e 2WD.. I didnt know this was going to be so easy...

    I already got a new NP205 and disassembled it so I could bore it out for the larger input bearing...

    Then Onetonbb74 hooked me up with the short 32 spline input gear for the tcase..

    Then I scored a nice th400->np205 adapter on ebay.. got lucky as the auction was only up for a couple hours and nobody had discovered the auction yet and "buy it now" was still available! Ive seen these adapters go for well over $300... I got it for significantly less.

    Ive pretty much decided on running GMPP's 4l80e/4l60e controller.. its big $ but i just have to bite the bullet. I found a company called "powertrain control solutions" and theirs was a couple hundred bucks less and was actually more programmable, but come on its GM here, I know it will be done right and the electronics will be built to survive. This bitch has to get me home. TCI & Compushift make controllers too but nobody had ONE good thing to say about either of those, and theyre more expensive than GM's.. easy choice.

    My main issues now are drawing up some plans for this adapter, and finding someone to cut it for me, along with the hole in the transfer case.

    this plan is finally starting to come together.. Ive had this 4l80e on the shelf for a few yrs now and im so excited to dump this bowtie overdrives 700r4, which has been nothing but a PITA.

    anyways, thanks for all the help folks, Ill keep you posted with progress and pics. Anyone interested in one of those adapters? Maybe Ill make two. no promises :)


    Mike
     

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