limited slip problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by gently, Sep 2, 2002.

  1. gently

    gently Newbie

    Sep 2, 2002
    Likes Received:
    i recently installed an eaton style limited slip unit in my 79k5 with a 3.73 ring and pinion. the pinion bearings were preloaded to the specs and the ring backlash was set to 0.009in. my axles were also worn so i used BCA repair bearings and the old axles. i drove the truck for about 450 miles with no noise or problems.

    then to my dismay, i began hearing a sharp knock, like the faint sound of gears not meshing correctly as i turned sharp rights at slow speeds (into my yard and such). the noise was only when turning right, and it could be changed in frequency or volume by applying the breaks. i was scared, so i dropped my pan, and everything looked alright (no metal floating around and everthing still in place).

    so i pulled the axles, thinking that an axle bearing didnt hold up, and to pull the unit and inspect it. the bearings still looked ok, and the axles didnt have any bright worn i cleaned the lsd and reinstalled it. i thought it might be 'walking' or the twisting of the lsd unit within the case, so i "tapped" it back in with 0.010 shims on each side...with the backlash still at 0.009 which was to spec.

    so i buttoned it up, and drove it again...and fu** if it didnt make the noise again. so i brought it back, opened it up, and now i see metal. looks like one of the spider gear bushings (thin discs between spidergears and carrier unit--the gears with the rod going through them) broke loose and fell out after getting crunched a little.

    so what have i got now. i dont know wether they are unrelated problems, and the noise is from something else, or if the carrier has some defect in it to finally break the bushing out. i need some advice, because im really lost.

    i was using Shell 85-90w gear oil (im told it's good stuff) and the hypoid gl-5 lsd additive from advance auto parts...the correct amount for the amount of gear oil used.

    if you read this (and thank you if you did, cause i know it's long), and have any advice, please give it to me.

    thanks in advance.


  2. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
    Likes Received:
    Roy WA
    Who did you buy it from? I can't believe you hear any noise from it, a true posi is typically (always?) invisible.

    I know the Eaton's are adjustable for posi "preload" but even then, shouldn't be tearing itself up.

    The "spider gears" you refer to are pinion gears, and I know the washers you are talking about. Is the pinion shaft (the rod that goes through them) in good shape or did you get a new one? I've seen ones worn down, if that thing allows the pinion gears to move around, then I could see your problem.

    If the shaft checks out good, I'd be talking to who you bought it from. That cup washer(?) you are talking about, shouldn't have failed. I've seen them worn, but this is in 20 year old units. I could also see the pinion gears getting heavily loaded if the side gears are sloppy, and moving into or away from the pinion gears, but I'd bet thats less likely than the pinion shaft being worn.

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