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edit: This Is NOT normal!? Front diff issues

Discussion in '80-Series Tech' started by slceso, Sep 9, 2017.

  1. slceso

    slceso ... pronounced "Jason" SILVER Star

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    This is a 1990 HDJ81. I was pulling up some shrubs today with my winch and some of the bigger ones maxxed it out, so I was pulling in 4L. The CDL was engaged but I was chirping tires on the driveway, so I engaged the front and rear lockers. I can't remember what, but something distracted me. I think the stump probably broke loose and I got out of the truck.

    The truck didn't move far, so I don't think the lockers ever fully engaged, but I left the switch on for several minutes and when I got back in realized that and turned the switch off.

    Somewhere in the process of this, when I was pulling s stump pretty hard, there was a really loud bang and since then I have a clank and occasional bang in the driveline. I think it is limited to the front diff, but may also be the tcase.

    Under normal acceleration there is a cyclical clank. If I engage the CDL in Hi or Lo the clank turns into loud bang that shakes the truck when turning.

    I'm looking for opinions on the following:

    1. I read that the elocker motor will burn up if you leave it engaged and it can't full travel. I haven't fully troubleshot the circuits yet, but now when I'm in Lo with CDL engaged and turn the locker switch to any position I get no dash lights. I can't tell if the control module solenoids are working or not. Best I can tell these are not fused. Dash lights work when the ignition is on with engine off (like all the other dummy lights).

    2. Can the locker partially engage? Wondering if it's in some mid travel position and just grinding the splines etc to death.

    3. What would you do? This is my DD. I don't think removing the front drive shaft will help. I'm not really setup (nor do I have the experience) to rebuild my whole front end. The closest cruiser mech is hours away and I don't think I can drive there in this condition. Here are some vids I took.

    Thanks!

    Edit:. There are 3 vids but the last one just linked and didn't embed.





    Clank from front driveline
     
  2. slceso

    slceso ... pronounced "Jason" SILVER Star

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  3. LS1FJ40

    LS1FJ40 SILVER Star

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    You weren't backing up and pulling were you?
     
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  4. fourtrax

    fourtrax SILVER Star

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    jack up the front one side at a time and turn the tire by hand a revs forward and backward, see if you can isolate it. you can pull the e-locker motor off/on pretty easily and move the shift fork between lock and unlock.
     
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  5. fourtrax

    fourtrax SILVER Star

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    jack up the front remove front drive shaft, remove the fill plug for the diff, spin the wheel and shine a flash light in the hole see if you broke a tooth of the ring gear.
     
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  6. slceso

    slceso ... pronounced "Jason" SILVER Star

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    Indeed. I'm guessing that's bad?
     
  7. fourtrax

    fourtrax SILVER Star

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    yeah, high pinions are weaker in reverse.
     
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  8. Douglas S

    Douglas S

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    Your front diff is almost certainly blown. When you open it up I expect the ring gear to be missing a tooth or two.
     
  9. slceso

    slceso ... pronounced "Jason" SILVER Star

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    I did pull the motor. I didn't try to get it to chooch. I need a helper to flip switches and such. I will probably put it on jackstands tomorrow and do a spin check on the wheels.
     
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  10. LS1FJ40

    LS1FJ40 SILVER Star

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    Yes. As stated, weaker in reverse. Sorry man. Doesn't sound good.
     
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  11. fourtrax

    fourtrax SILVER Star

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  12. slceso

    slceso ... pronounced "Jason" SILVER Star

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    So now the question is do I JUST need to rebuild the front diff, or that and both elockers?!

    Time to buy a craigslist burner car...
     
  13. fourtrax

    fourtrax SILVER Star

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    i think worse case is a new ring and pinion. you can pull the 3rd member and take it to some place like ECGS and they can have it back and running in a couple days. it could be something else, but, im leaning towards a broken tooth. :(
     
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  14. slceso

    slceso ... pronounced "Jason" SILVER Star

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    lets hope..
    upload_2017-9-9_22-43-20.jpeg

    I've been considering a re-gear due to the 35s and 134 hp at the wheels anyway. I'm just hoping I don't have to buy new elocker moto/actuators.
     
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  15. Rice

    Rice SILVER Star

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    Locked, in reverse, and on pavement?

    Yeah, there is a fair amount of documentation (I.e. Carnage) regarding high pinion diffs in reverse. Sorry for your loss.

    If you need to drive it some where you'll need to pull the front driveshaft and remove the drive plates, then rig up a nice cover over the hubs and lock the center diff.
     
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  16. slceso

    slceso ... pronounced "Jason" SILVER Star

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    drive plates = that guy in the middle?
    [​IMG]


    is this a good time for longfields, bearings, seals?
     
  17. mudgudgeon

    mudgudgeon

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    People underestimate what it takes to pull a tree stump.
    There's tree stump pulling car related carnage all over the Tube of You!
    Chains, stumps etc flying through car windows. You might be lucky if it's only blown R&P.

    A landcruiser is not a tractor, even if they sometimes sound like one.

    I don't think it's likely to be diff lock actuators.
     
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  18. mudgudgeon

    mudgudgeon

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    Yep, drive plate is on the end of the hub. pull the dust cap, the c clip, and the six lots of nuts and cone washers. I've used duct tape in the past to temporarily seal up the hub.

    If you indeed have blown the ring gear, it's definitely an ideal time to rebuild the front hubs while you're in there.
    Longfields are probably over kill fit most people, unless you make a habit of pulling tree stumps :rofl:
     
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  19. slceso

    slceso ... pronounced "Jason" SILVER Star

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    In my defense, they were shrubberies!

     
  20. ppc

    ppc M Go Blue

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    There is a 30A "DIFF" fuse on the fuse panel to the left of the steering wheel that feeds the Diff ECU, Dash lights etc. I doubt that you will need to rebuild the actuators.
     
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