how do I tell if it is really a limited slip?

Discussion in 'Diesel Tech / 24 volts' started by Chang-kuao-lo, Feb 19, 2009.

  1. Chang-kuao-lo

    Chang-kuao-lo

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    I was looking at the BJ42 the other day while it was on the lift at the mechanic's shop, while he was showing me how the new brake shoes don't fit, and I noticed the "LSD only" sticker on the diff punkin. Now, how can I tell if this is really a limited slip, or if some PO just decided to slap a decal on it because it might look cool? I don't know much about differentials, so type it slow so's I can understand.
     
  2. amaurer

    amaurer

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    If you have a semi float, just pop the diff cover and have a look. If the diff has a bunch of springs and stuff in it, its an LSD. If its just gears, then its not.

    If you have a full floater then it'd be a bigger chore, I'd put it in 2wd and stick it in some kinda ditch such that one rear wheel comes off the ground. Then see if you can move. :)
     
  3. sandcruiser

    sandcruiser

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    or throw the bottle jack under one side of the axle and lift one tire off the ground (barely).

    jump in, put it in low, try to drive forward (slowly).

    if you move, you've got an lsd. If you don't move= open diff.

    Be gentle as you don't want to damage the jack.
     
  4. Chang-kuao-lo

    Chang-kuao-lo

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    It's a full floater. Ill try the floor jack, it has wheels. Rolling off a bottlejack or an axle stand sounds like it would be rather unpleasant. :) Thanks for the "tip o' the day".
     
  5. jasonmt

    jasonmt

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    Both rear wheels off of the ground in neutral and spin one wheel, if it is a clutch type limited slip both wheels will spin the same direction.
     
  6. Chang-kuao-lo

    Chang-kuao-lo

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    Oh ok, I remember putting chains on a fire engine once and noting how the other wheel would spin in the opposite direction when it was off the ground. Is the factory Toyota LSD a clutch type?
     
  7. crushers

    crushers post ho

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    LC semi floater can not have a limited slip, there is no access for the retaining C clips.
     
  8. amaurer

    amaurer

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    oh. whoops. :eek:
     
  9. sandcruiser

    sandcruiser

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    jacking up and spinning the tires is a much safer way to check than my approach.

    Ignore my previous post.

    put tranny in neutral, parking brake off, both rear tires up. If you can spin one tire and keep the other one stationary then you don't have LSD
     
  10. crushers

    crushers post ho

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    or
    it might be a badly worn out Limited slip...
     
  11. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    IMOP the Toyota factory LSD are barely mild .. I can see Nissan LSD from 82 still working fine .. and my LSD on my 80 series doing nothing ..
     
  12. Gold Boy

    Gold Boy

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    on my lsd 74, i jack up the rear end, and get a friend to hold one of the rear wheels whilst i turn the other wheel, that wheel i turn almost instantly grabs and both wheels are "locked".
     
  13. crushers

    crushers post ho

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    on factory limited slips that are now slipping a lot.
    remove cneter section
    tear down limited slip
    sand blast the clutch plates and discs
    add 1/4" shims
    reassemble
    reinstall
    add LS diff suppliment

    very good traction now... for quite a while.

    cheap, effective...
     
  14. Chang-kuao-lo

    Chang-kuao-lo

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    Good to know for future reference. The oil that came out was pretty brown and sludgy. Lots of water contamination, hopefully not so bad as to muck up the LSD.
     
  15. jasonmt

    jasonmt

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    Depending upon how "tight" the LSD is you also get some clutch material in the oil, the colour and material in the oil can be a bit of a mystery if you do not know that there is a LSD in there.

    On the Super Duty Fords with the LSD the rear diff oil comes out looking like it has been contaminated with moly grease even with only 5000 km on the oil.
     
  16. Chang-kuao-lo

    Chang-kuao-lo

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    Oh no, both diffs came out pretty brown. And there was a lot of mud caked into the nooks and crannies. I think this thing did it's fair share if creeks and mud bogs. The E brake is siezed, and it wouldn't surprise me if the cable housing is packed with silt. The PO apparently didn't realize that the E brake was siezed, and kept on driving. The result was the destruction of the entire rear brake system. Either that, or the PO knew, but didn't care. Ignorance or apathy, the root of all the world's problems...


    "IMOP the Toyota factory LSD are barely mild", do you mean the OE LSD is on the weak side? I that what you mean by "mild"?
    As an aside, if I install a selectable locker, this would replace the LSD entirely, yes?
     
  17. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    Most of LSD have 70/30 rate traction .. I never seen Toyota LSD ( never perform a profesional or scientific test neither ) perform anything better than a 70/30 new .. with a few years on it it go complete useless ..

    Most of the 80 series and 100 series here come with factory LSD ( few 60 series ) and neither works .. instead Nissan LSD are still working ..

    And yes .. with a locker you would replace the entire case .. ( even with a detroit, ARB or factory cable or electric locker .. )
     
  18. Chang-kuao-lo

    Chang-kuao-lo

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    That's what I thought. By 70/30 rate, do you mean the traction differnce between wheels?
     
  19. sandcruiser

    sandcruiser

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    power distribution= 70% to one wheel, 30% to the other
    I'd love to have LSD in front. If I had factory LSD in a 40 or 60, I'd put it in the front and go with an ARB in the rear.

    I know... lots of folks will poo-poo the LSD. But I don't do hardcore rocks. Mostly mud and sand. A little extra traction up front would go a long ways for me and I think an LSD would retain most of the handling in 4wd. A selectable might do more for me on traction, but I"m afraid of breaking stuff so would rather get a little stuck than a little "oops, there goes the birf"
     
  20. crushers

    crushers post ho

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    i have run my modified LSD in the front on a few trucks, it does help.
    when you tear into one there is not "clutch material" it is the design of the metal disc that cause the traction aid.
    once it is shimmed then the increase in traction is very noticable but still steerable and will slip before a birf bits the dust
    now it is either open or selectable (and that being said i just picked up a Oz locker for the front and back of my FJ75)... what a hyprocrite, eh?
     
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