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Diff Differences

Discussion in '70-Series Tech' started by Behemoth60, Aug 14, 2005.

  1. Behemoth60


    Likes Received:
    Sep 22, 2004
    If you're planning a gear swap in your cable locked JDM truck, here's some advice for you. (I just installed 4.88's into Ziplock this weekend).

    The diff will only come out of the housing if the locker is engaged! It's only possible to engage the locker with the axle shaft in the housing. When romoving the axle shaft from the housing, sometimes it can pull the locking mechanism out. Use a flashlight and look down the axle tube to make sure that locker is engaged. This will make life a whole lot easier.

    The newer diffs do not use the screwy screw-in bearing caps to adjust backlash. They use shims behind the bearing races to set backlash.

    The bad news is that if your new gears do not setup with the same backlash setting, then you need an extensive set of shims to do a gear set-up.

    However, when swapping from 4.11's to used 4.88's both of my diffs set-up perfectly. The rear diff needed pinion shims to set the rear pinion depth, and as the depth got closer to correct, the backlash got better too. When the pinion depth was perfect, so was the backlash! Backlash, run-out, and pinion depth all set-up perfectly. On the front diff, I didn't even have to change the pinion depth at all and found it to be perfect. The backlash is just .0002" outside of spec, but I'm not going to worry about that for a front diff.

    The even gooder news is that adjusting pinion depth is MUCH easier with this new design. Without having to adjust the spniners and backlash in the side bearing caps every time you checked pinion depther, the process to set-up the diff took me at least 1/2 the time as normal.

    The even goodest news is that these screwy screw-in bearing cap retainers were a weakness in the old diff designs, and I've know of at least a handful of trail troubles caused by this design.

    The even more goodest of the goodliest news is that the carrier design is extremely strong. No dinky cast carrier like the old diffs... these bad boys are solid machined steel. They look like, and are about the same size as an ARB Air Locker carrier. Much more robust that the old carriers, I would reckon.

    That's all I have to say. Please go back to your regularily scheduled h8ing of mud.

    Peter Straub
    TLC Norway likes this.
  2. Stone

    Stone Moderator

    Likes Received:
    May 13, 2004
    BC, Canada
    Thanks for the info, Peter. I think I'll link this to our FAQ.
  3. Tapage

    Tapage Club 4X4 Panamá SILVER Star

    Likes Received:
    Apr 4, 2003
    :oops: are bad notices .. ! shims .. I hate the shims .. put, measure, not are bad, go out, other shims and again the same proces .. !
  4. crushers

    crushers post ho SILVER Star

    Likes Received:
    Feb 10, 2004
    Tara Ontario
    Morning Peter,
    care to expand on this statement as i have not seen any failures do to the adjusting caps...