Need guidance on adjustment

Discussion in 'Transmission & Driveline Topics' started by Fbird, Dec 4, 2019.

  1. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    02 F150 9.75 posi rear diff in my truck.
    Problem: clutch "shimmy" during tight turns with acceleration
    Long history:
    Lost axle bearing chewed up axle. rebuilt rearend all bearings swapped to 4.56 gears! clean inspect clutch pack...assemble add ford modifier to 75-145w synthetic. ALL IS WELL!!!
    forward 4 yrs....
    lost "replacement axle: :( (just started to humm) disassemble clean inspect replace both axles YOUKON and axle bearings !!!!!! 75-145 lube + 1 bottle modifier

    Problem starts:
    noticed immediately after warm up, test drive that clutches were "tight".... do a few figure 8's to work the clutch lube in (i did put them in WET) drive a week...still "tight" CLUTCH BITE!!! (kick in the ass sideways)
    ADD A 2ND BOTTLE OF MODIFIER
    this helped but still get a "shimmy" when taking off/turning ...NOT CLUTCH BITE ...but a shimmy.

    MY recommended FIX (heres where i need some input)
    Remove C-clips and grind .002-.003 off each ...re install. (i am a 25+ yr Tool & Die maker...this is not a challenge)
    Is .002-.003 ENOUGH or should i be a little more aggressive? like -.005
    OR
    add yet another bottle of modifier?
     
  2. Knuckle Dragger

    Knuckle Dragger Mayor of Simpleton Staff Member Lifetime Gold Member

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    When I was with Ford their solution was more friction modifier. That was 10+ years ago.
     
  3. big gear head

    big gear head Veteran Member

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    I'm not sure that I understand how grinding the c clip is going to fix this. Clutch preload is set with shims, not by the c clip.
     
  4. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    clutch pack is compressed by crosspin to axle button to clip to axle gear to clutch pack

    The only thing that has changed is the axle. so if the "button" tip is say .005 too LONG it would preload the clutch pack MORE.

    clutch pack is loaded by multiple belville washers. I know that on a clutch pack .005 can make a BIG difference as a bellville "spring" is high pressure with very limited apply distance
     
  5. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    probably try 1 MORE bottle first..only $8 ...no mess ..no work...lol
    THEN if its still not right i will THEN get into some actual work
    Thankyou
    Greg
     
  6. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    [​IMG]
    [​IMG]

    #47.....
    not like GM that applies spring pressure from the INSIDE pushing outward. Shimming between carrier and axle gear/spider gear/axle gear- carrier.
     
  7. big gear head

    big gear head Veteran Member

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    #46 is a shim. Are the axles pressing against the cross shaft or is there clearance? If the axles are pressed against the cross shaft then how did you get the cross shaft in after installing the c clips?
     
  8. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    i use a 3/8" bolt and a nut ...between the axles and "jack" them apart to compress the clutch pack... yes axles are 100 against crossshaft.
    There is a special tool for compressing the clutch packs... (yeah like i'm going to have that..)

    I see there is an axle ENDPLAY measurement .030 max....that would dictate that the axle is NOT ..should NOT be against the cross pin...HHHMMMM.

    I do recall the axles having an -O-ring in the clip slot...figure its just an "anti-rattle" "device" as it is toward the wheel side..not toward inside..
    But definately know there is NO .030 clearance TOTAL between the cross pin and axles.
     
  9. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    I still have the OE axle.... guess I will have to open it up and pull them out to measure WTF. did not realize there was an axle endplay spec. as the OE axles seemed to rub the crosspin when I was removing it...but that was 5 yr ago...working on a MESS. Looked like a bottle of glitter exploded...chewed up axle
     
  10. big gear head

    big gear head Veteran Member

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    Please come back with your results. I want to know how this works out.
     

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