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Thread: Mk4: mounting IRS diff... extra space at mounting point bushing and the diff. flange

  1. #1
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    Mk4: mounting IRS diff... extra space at mounting point bushing and the diff. flange

    Got the differential muscled into position, but the front mounts show space between the flange of the differential and the bushing.
    If I insert the two washers (shown), which takes up the space, the steel sleeve sticks out on the other side of the bushing.
    When the flange nut is tightened it is prevented from touching up to the bushing, because the two washers prevent it from reaching the diff. flange.

    Do I not bother in trying to close the gap (leave any washers out) OR do I shorten the sleeve by about 0.230" and use the two washers and tighten it all up?
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  2. #2
    Senior Member edwardb's Avatar
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    I didn't experience that with my IRS builds, But this has been posted about several times by other builds. Per Factory Five according to this thread, it's "normal" and OK.

    https://thefactoryfiveforum.com/show...l=1#post543900
    Build 1: Mk3 Roadster #5125. Sold 11/08/2014. Build 2: Mk4 Roadster #7750. Sold 04/10/2017. Build Thread
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  3. #3
    Senior Member CraigS's Avatar
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    I wonder if they increased the space to make it easier to get the diff in and out.
    FFR MkII, 408W, Tremec TKO 500, 2015 IRS, DA QA1s, Forte front bar, APE hardtop.

  4. #4
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    Thanks all! I also read the post & link from 'edwardb' and with all the discussion I'm now thinking about it differently.
    With no washers for the front two mounts there will be a slight gap for each, but with the bolts torqued to spec,
    the sleeve will be so tight to the differential's flange, it will be like a stud or mounting pin sticking out from the diff. flange and it
    will be supported within the bushings. The space will be inconsequential. The strength of the front mounting will be fine.
    I don't believe it's a case of too much extra clearance that somehow "fretting" will take place, thereby worsening the gap.

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