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vss to cable drivin?

Discussion in 'The Garage' started by nerraw117, Aug 12, 2005.

  1. nerraw117

    nerraw117 1/2 ton status

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    ok here is my problem. i have a 85 k5 with a 90 engine in it. the PO rewired the whole truck with the 90 wiring. i have a 79 transfer case with cable drivin workings. so i would need a a older speed which i have out of a 79, dont work cause of 90 wiring. i have 90 guages , everythign works but speedo. is there a device that converts the vss where i can hook up a cable to get the speedo to work with my 79 drivetrain? i know there is but i dont know where to look and i have seen some for 200 bucks but i have heard there is also some for like 50. can anyone help? :dunno:
     
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I know of a box from electric TO mechanical . You want to from mechanical TO electric speedo ?

    You can buy a sending unit that threads onto the speedo drive on the case or trans , and ouputs electronic signal . I couldn't say how to wire it , but are less than 65 at Jegs .
     
  3. nerraw117

    nerraw117 1/2 ton status

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    where are these parts? whatever works man lol

    i have a manual drive t-case and a vss speedo
     
  4. dirtwarrior17

    dirtwarrior17 Banned

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    Stick with the vss if you can get another one for cheap... the cable driven aren't any better... my speedo likes to bounce the needle up and down and i never know how fast i am goin.
     
  5. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    I think I got my VSS from Turbo City. I still have a cable speedo but the VSS signals the ECU so I presume it would drive a speedo too. It connects inline at the t/case.
     
  6. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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  7. nerraw117

    nerraw117 1/2 ton status

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    yea im looking for the exact opposite. my speedo is vss, but my transfer case requires a cable. so i dont know hoe to get my speedo to work.
     
  8. nerraw117

    nerraw117 1/2 ton status

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    i must be extremely lost. i thought it understood what i needed, but i dont. i have a 90 engine, that has the vss guage. but i cannot hook it up cause my transfer case has a cable hook up. so i am super lost :dunno:
     
  9. southernspeed

    southernspeed 1/2 ton status GMOTM Winner

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    Like I say, the VSS i used connects to my '78 cable driven t/case, inline with my cable driven speedo. The signal the VSS sends out goes to my '90 ECM for my '90 engine.
    If you don't have a VSS already your engine management system would like one.!! I'm sure you can hook up an electronic speedo to this same VSS signal. Have a word with Turbo City and see what they can suggest. Also do a search on here for drac posts. There have been a few interesting ones.
     
  10. 73k5blazer

    73k5blazer Unplug the matrix cable from the back of your head Premium Member

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    The VSS trucks I've seen still have a cable running to the speedo from tranny or transfercase, just the spedo has a little wire pigtail coming off it to a little box, which is the VSS signal.
     
  11. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    This threads onto where the cale connects to the transfercase . You would need to find out how to wire it . It also has a threaded end so you can still attach a cable to it as well . Its by Autometer and available everywhere their parts are sold . You can do an internet search . Pic if it do't show

    [​IMG]
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    Yep, jagsthatrun I'm sure sells what you need. You need a VSS signal generator that is "inline" with the speedometer cable. The picture posted is exactly of that. The wire(s) off the generator run to your ECM, the speedometer cable just threads into that piece, which is threaded onto the transmission.

    Personally, I'd spend the time/money/effort to get rid of the cable drive stuff, but not sure whats out there to do it. The stock '90-91 DRAC would work, but you'd need a generator for 40 pulses per output revolution, not the 2 pulses per cable RPM that the '89-older stuff requires.
     
  13. Canadianbuilder

    Canadianbuilder Registered Member

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    Your best bet is to find an 87 pickup or 87 to 89 sub ,blazer or crewcab donor truck at the scrap yard or possibly one someone is parting out.Use the cable driven speedo with vss built into it from that and grab the wiring harness that runs from the speedo to the ecm.If the wiring harness won`t plug into your ecm then grab the ecm from the donor truck as well.The ecm`s are fairly easy to get at by removing the glovebox.
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    True, easier/more common option would be to get *any* '81-89 C/K (R/V) instrument cluster that has the hole tapped for the VSS optical "eye". VSS is not all about EFI, it was used for cruise control long before trucks went TBI.

    Anyways, just grab the buffer with the cluster, the wire that I'd bet runs to pin A10 on the ECM (that seems standard for a lot of the same year ECM's) on the '90 stuff would just be spliced into the older clusters VSS buffer output.
     
  15. nerraw117

    nerraw117 1/2 ton status

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    do yall think it would work if i go to say autozone or any parts store and get a factory VSS to plug into my transfer case, would that work?
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    No. '90/91 t-cases are the ONLY ones that can utilize the VSS mounted on the case, stock. (241/205 only) You can make the reluctor ring fit older cases of course, just additional work. Retrofitting the ring has been covered on this board.
     
  17. nerraw117

    nerraw117 1/2 ton status

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    ok so i am completely lost, and about every post has been something differant. how can i get my speedo to work with my 90 guages, with my 79 203 transfer case?
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    Easy answer? You can't.

    '90-91 are the only setups that used the electronic speedometer, which REQUIRES a tranny mounted VSS. (talking stock here) The NP241 and 205 for those two years are the only t-cases that had the VSS mounted to the t-case. '90-91 241/205 are the only stock t-cases that can be used to make your gauges work as they should. Clear?

    EVERY C/K/R/V '89 and older uses a speedometer cable and mechanical speedometer. (for clarity, I mean the old body style '89-older)

    I don't think anyone has said anything incorrect or that differs from anyone else on this post, if so, it's been mentioned.

    The only way you will make your cluster work with stock parts is to swap transfer cases to the '90-91's.

    What everyone else has been saying is how to get around the hassle of swapping the transfer case.

    I'll change my first statement, even though it IS the easy answer: You can make your '90 gauges work, but it's not going to be a simple drop in affair no matter how you look at it. If you want the '90 gauges, you are going to have to do some work and spend some money.
     
  19. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Maybe these will work , they are meant for th350's and 700r4's . Maybe they bolt on to np203's too ?????

    The bolt in part replaces the speedometer cable hookup , and you can change the gear on the inside that gets driven by the tranny/case .

    Possiblity , I am going to go home and take a look at my new found 203 and see what the speedometer hookup looks like , and compare to my 2wd th350 and my np208 .

    [​IMG][​IMG]
     
  20. dyeager535

    dyeager535 1 ton status Premium Member

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    The output is 4 pulse.

    The '90-91 setups require 40 pulse to the DRAC, and all previous trucks are 2 pulse.

    That's designed for GM cars.
     

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