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Thread: gear patterning help: stuck

  1. #1
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    gear patterning help: stuck

    Fellas im trying to pattern my supra diff and frankly im annoyed. The pattern is properly set as far as the centre of the face but it is to close to the toe end on the drive side of the gear. Directions say to open up the backlash but at max spec im still not seeing results. I want confirmation on my thoughts.
    edit: according to 4x4 guys

    Note that changing pinion depth also changes backlash. Increasing pinion depth (removing shims) decreases backlash; decreasing pinion depth (adding shims) increases backlash.

    which might help



    Last edited by TTC; 03-03-2012 at 06:47 PM.
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  2. #2
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    Also keep in mind different patterning for used gears.
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  3. #3
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    Face/flank = Pinion

    heel/toe =crown

    As said your pattern looks good in the face and flank. Your pattern is heavy in the tow on the drive side and a touch further into the heel than I'd like to see in the coat side.

    being heavy in the Toe is actually okay. As the torque is applied the crown gear and pinion will "walk out" from each other as the third member flexes. That pattern will not result in any damage.....just some slight noise when you are coasting just between accel and compression decel.

    I would add that this pattern is very typical of high mileage crown and pinion gearsets. They just lapped into each other over time and thats the result. set the backlash somewhere between 0.004" and 0.010" and tweek it a bit but don't be too worried. At the end of the day you have what is considered an acceptable pattern.

    Hope that helps.


    Or you could have said "sorry, my kidnap victims keep kicking my elbow, it made me drop my crack pipe and swerve"

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  4. #4
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    Oh and if you are hell bent on a better pattern then try a slightly thinner pinion spacer. Then reset the backlash and clearance it for best pattern. Make sure you seat the side bearings after setting backlash by hitting the crowngear on both sides with a rubber hammer.


    Or you could have said "sorry, my kidnap victims keep kicking my elbow, it made me drop my crack pipe and swerve"

    -bangnscrape

  5. #5
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    I took out 3thou from the pinion spacer and it went all to hell lol ... ungh bastards .. Drive side ended up going high on the foot side and coast high on the toe side. I guess I will go with what I had before. Then again, 3thou isnt exactly slightly thinner.
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  6. #6
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    Quote Originally Posted by TTC View Post
    I took out 3thou from the pinion spacer and it went all to hell lol ... ungh bastards .. Drive side ended up going high on the foot side and coast high on the toe side. I guess I will go with what I had before. Then again, 3thou isnt exactly slightly thinner.
    I just want to be clear. When I say pinion spacer I am referring to the spacer between the inner pinion bearing and the pinion itself. I am not referring to the spacers commonly used on solid spacers that take the place of a crush sleeve.


    Or you could have said "sorry, my kidnap victims keep kicking my elbow, it made me drop my crack pipe and swerve"

    -bangnscrape

  7. #7
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    NOno, the pinion depth spacer not the crush sleeve. The crush sleeve is for pinion preload.
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  8. #8
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    what Chris says. heel-toe won't result in gear breakage, as long as the contact is centered on the face. Just possible noise under certain conditions (heavy decel) IOW, good enough. And slightly-toe contact on the drive side is desirable.

    If this is a rear diff, you're good to go. If the gears came out of this carrier and you're just installing a LSD, you're good to go. If you're re-gearing, you could try again, but you might be putting it back again too.

    003 is thinner. my shim increments allow 001 change, fwiw.

    IMO put the original stuff back, make SURE that everything is seated using the deadblow hammer before you do a re-pattern. And if you're using a crush sleeve in your setup, be sure that it's in place. If you're re-using the collapseable spacer, you can slip a 010-020 shim in there (if you have one that fits properly) and re-use.

    I usually set gear clearace to 008-010. Never below 006 to prevent gear binding, they expand quite a bit when they get hot. And I preload the efff out of the side bearings. I use never-seize to lube the threads on the rings, and a BIG pin wrench. Often use a pin punch and a hammer to get those things TIGHT.

    Also, use wrenches when you roll your pattern, put as much torque as you can against the gears.
    - Brian


  9. #9
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    Yeah, I agree. I use an older ford 9 inch spanner for setting preload on those side bearings. You can make one using flat stock and two bolts through it. I set them to zero backlash and then get the desired backlash by tensioning the bearing on the same side as the ring gear teeth.


    Or you could have said "sorry, my kidnap victims keep kicking my elbow, it made me drop my crack pipe and swerve"

    -bangnscrape

  10. #10
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    Sticky this. For chris is crazy knowledge man of the rear end. Keep it tight Sir.
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  11. #11
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    All pretty good info. For the stuff Myself and work setsup, i do backlash by hand usually, and dont run that much crush/pinion preload. also, if your running junk like Koyo, be carefull how much preload that is ran. There races are soft as hell. then again, we build mostly track crap, so noise is not an issue. If they were new gears, i wouldnt send that pattern out.


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  12. #12
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    Gears in, sadly they whine a bit under no load or slight load. Also how long can you go on a noisy throw out bearing lol
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  13. #13
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    FYI. they real god damn noisy now lol.
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  14. #14
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    where's the like button
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  15. #15
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    Quote Originally Posted by TTC View Post
    FYI. they real god damn noisy now lol.
    This is a good post.

  16. #16
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    Do new gears help?

    Do they wear out? Will some old gears just make noise no matter what?


    RETIRED

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    Dropped pizza in lap

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