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pinion angle and shackle reversal??

Discussion in '40- & 55-Series Tech' started by cruzer, Jan 23, 2003.

  1. cruzer

    cruzer

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    My truck(75 FJ40) currently has a shackle reversal kit on it. The kit is similar to man-a-fre's BUT it did not flip the spring pack around...i.e. the long side is still forward. The SR is gives the truck some lift(maybe 2.5inches?). The shackle in the front is very very short..like just enough room between the spring eye and the frame to not rub? My pinion is pointing straight back and not up at all. Is this correct or should i put some shim's in there to point the pinion at the xfer flange? I only have 235's on there now but am going with some 34" LTB's this spring (can we say tax return)...

    Stew
     
  2. JasonH

    JasonH

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    The pinion angle isn't as important as your caster. If you point the pinion toward the transfer case (without cutting and turning the knuckles) you'll have very negative caster which will make your rig wander like crazy down the road.
    As long as your caster is good, don't mess with it. That's the reason those aftermarket shackle reversal systems hang down so low in the front. It's to keep your caster near the factory setting.
     
  3. woody

    woody Internet Fireman Staff Member

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    Jason's right...on my old suspension setup I had the pinion pointing slightly down to add in more caster and help it track better while on the tow-bar.

    If you want the pinion pointed at the t-case, you must cut-turn your knuckles.

    Find the Tom Woods driveshaft (http://www.4xshaft.com, I think) and his tech stuff has some good info on d-shaft angles.