LOW WITHOUT CENTER DIFF LOCKED

Discussion in '80-Series Tech' started by Beast II, Apr 4, 2003.

  1. Beast II

    Beast II

    Messages:
    732
    At times, I'd like to be able to put the FZJ80 in low gear without the center diff locking automatically. Is there a way to do this ?
  2. semlin

    semlin rocker SILVER Star

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    5,147
    Location:
    north of 49
    umm, just curious but why?

    you can start by getting a central differential lock switch if you don't already have one.
    SenorSmartyPants likes this.
  3. Wrench

    Wrench The World Hates Me

    Messages:
    4,022
    semlin is right. In order to do that you need a center diff lock switch installed in the dash. Very easy to do. 10 minutes tops to do. You can get one from sleeoffroad.com They are about $50.
  4. Rogue

    Rogue

    Messages:
    968
    Location:
    Jefferson
    The Center Diff Lock switch is only the first step to achieving an unlocked center diff in low range. You will then have to either remove a plug directly from the t-case, or do some modifications to your wiring. Both options have thier ups and downs.

    It is not as easy as just installing a switch.

    BTW, I have installed the switch and 10 minutes is a good estimate if you don't plan on removing any screws and just ripping the dash panel off, but plan on 20-30 minutes to do it right and make it nice.

    I have not yet done the mod to run without the center diff locked in low. I haven't needed it, so haven't wasted time on it. If ever I do, I will do the wiring mods and leave the connector on the t-case so I don't get muddy goop in my connections.

    Hope this helps...
  5. Matt,
    The wiring mod mentioned by Rogue probably didn't make it from SOR over to this forum. CruiserDan posted the mod and it basically enables you to keep the plug on the Xfer case, keep the low-range tranny shift points, and allows the CDL switch to control the locking/unlocking.

    Post back in this thread if you are interested in the details and he will post the details here on ih8mud.
    -B-
  6. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator Supporting Vendor

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    Sniffin' diesel
    The Wulf is correct...................... :bow:

     If you wanna know, I'll do it again.

     Don't ask until you put the switch in..... 8)

    Rogue,

    It's not a waste of time. Think of it as being one of maybe 3 or 4 people on the planet who even knew it could be done......

    Knowledge is POWER............ :bow:
  7. Rogue

    Rogue

    Messages:
    968
    Location:
    Jefferson
    Okay Dan. I guess I should do it now just in case I need it later. Let me know what I need to do.

    Thanks... :bow:
  8. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator Supporting Vendor

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    Rogue,

    Ask and ye shall receive:

    Remove the dead pedal and the left front sill plate. In the left kick panel you will find a Silver metal box. That is the ABS ECU. Remove it, and behind you will find a black plastic relay about the size of a cigarette pack. It says "transmission control relay" on it. That's what you are after. The EWD calls it the "center diff lock relay", same thing. Unplug the harness from it and take a terminal pick and remove the black wire with blue tracer from pin#7. Insulate the bare terminal to suit and then put everything else back where you found it. If you have the low 4 position swith at the transfer case unplugged, crawl under there and reconnect that as well.
    What you have just accomplished is you have interrupted the signal from the transfer case that tells the lock ECU that you went to low range but you are still sending a signal to the transmission ECU telling it that you ARE in low range. Therefore the transmission will shift in the correct low range pattern. In addition you now have true manual control over center diff locking. It only locks when you tell it to without regard to transfer range selection.
    Oh, I forgot the final step......Grab yerself a congratulatory #6 (but not an English one as you have just performed an electrical task, sorry Jim)

    Regards.......Dan :beer:
  9. pismojim

    pismojim the Dude abides... SILVER Star

    Messages:
    1,053
    Location:
    Pismo Beach
    Can anyone describe how the shift pattern changes from low to high range? &nbsp:Does it shift up/down sooner/later?

    I got the switch in, and unplugged the plug a few years ago.
  10. Rogue

    Rogue

    Messages:
    968
    Location:
    Jefferson
    Thanks much Dan. :bow:

    Maybe I will find some time in between classes this week to tear aprt my truck and put it back together even better than before.

    Wish me luck.  I will need it.  What will likely happen is me posting in a few days with something like...

    'I fried my electrical system and need to get a new ECU and entire elec. harness.'  Don't know if it is possible, but if it is I will manage it.

    Later...
  11. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator Supporting Vendor

    Messages:
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    Location:
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    Jim,
    The transmission shift points move up in low range, it also downshifts earlier. It is difficult to verbalize but very noticeable.
    You can check it out like this:

    Shift into low range and transmission in drive. Accererate moderately. The trans will go 1,2,3,od quite rapidly.
    Stop and crawl underneath, plug the low 4 position switch back in and repeat the test. You will find that the gears hold for much longer, and when you let off the trans downshifts.

    Give it a try...................

    Regards....Dan :beer:

  12. ParadiseCruiser

    ParadiseCruiser

    Messages:
    620
    Rogue -

    Not to worry, it's a piece of cake - did it in my sleep ;)

    -R- (Previously res of Coquille)
  13. thorvald

    thorvald ....... SILVER Star

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    mine came with it '91 :D :D :D :D :D
  14. Rogue

    Rogue

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    968
    Location:
    Jefferson
    See the problem is not installing the switch. It is messing with the wiring that worries me. I already have the switch in my dash. That was an easy one.

    I will give the wiring mod a shot this week. If everything gets fried I will likely be importing a couple of New Mexicans to good ole' So. Oregon.

    :bow:New Mexicans...
  15. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator Supporting Vendor

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    Location:
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    Rogue,

    Ice down some Boddingtons, I'm on the way.........

    Oh, S**t wait...Those are English.........

    Make it Fat Tire......... :beer:
  16. Rogue

    Rogue

    Messages:
    968
    Location:
    Jefferson
    Modification finished.

    It went well, but I did need to make a call to one of the Cruiser gods just to make sure I was doing it correctly. :bow:

    After a quick test drive on the local logging trails the verdict is good. I like the feeling of the truck unlocked in low, and the shift pattern is great. No more BANG, BANG, BANG!

    Any day that I get to work on the Cruiser is a good day. When the work is free and it makes the truck better, that is a great day.

    Thanks for making today a great day Dan. :D
  17. Beast II

    Beast II

    Messages:
    732
    Gentlemen:

    Thank you for all of the help. Question answered ? Now lets see if I can do it without electrocuting myself :D

    Matt
  18. erics_bruisers

    erics_bruisers

    Messages:
    2,041
    Watch out though -- I DID lose 2 of the same screw doing this -- the one that's at the top of the cigarette tray slider -- I couldn't recover them!

    :dunno: :dunno: :dunno:

    e
  19. yomama

    yomama

    Messages:
    291
    Just a note that this is a good mod to have done. When I have to move my boat around I use low range, if it was locked it could create a binding type effect. When ever I put my boat in or out of the lake I always just use low and not locked, pretty impressive in low and unlocked, so far that is all I have needed. I was even pulling my boat out of a sandy launch where I was waiting for the guy ahead of me. He had a 12' boat trailered to his two wheel drive Chevy. He launched the boat, got back in his truck and proceeded to dig down in the sand, with nothing but a small trailer attached. He made some nice holes by the time he got it out of there, going back and forth. I thought "oh my god" I will never get my boat out of there, shoot, low range not locked, didn't even spin one wheel. I love my truck.....

    Yomama
  20. Beast II

    Beast II

    Messages:
    732
    I'm always a bit apprehensive when dealing with the electrical system. I don't suppose anyone has pics of the wires ? I know its a long shot.

    Matt

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