Rear Differential Knocking Sound

Posted by Moonlight GSX, Jun 28, 2011
Newbie Forum - Beginner DSM modification questions and discussions. Common, repetitive, and general discussions will get dumped here from other tech forums. Unless you're a Probationary member you shouldn't post threads here.

  1. Moonlight GSX

    Moonlight GSX Supporting Member

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    Downham Market, Europe
    After looking through the forums I didn't, again, find exactly what I was looking for. Related to the rear differential, is it supposed to actually make a "locking or knocking" sound when going into reverse? Or even when shifting in 1st-5th? It's almost as if the transfer case is "free flying" when I'm off the gas and re-engages when I get on it again. As for the reverse portion, that knocking sound always comes up when going backwards as if there is a bit of "space" floating between the forward and reverse points... should I just have the transmission, transfer case, and rear differential rebuilt (was planning on doing this later)?
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  2. Alan11

    Alan11 Proven Member

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    If it clunks every time you shift, your rear differential bushings may be bad now..

    It really depends on how it sounds. are you sure its from your differential.?
    #2
  3. jtmcinder

    jtmcinder DSM Wiseman

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    Lots of 2Gs have excessive backlash in the rear diff. It's not only annoying, but it can greatly increase the odds of the rear diff exploding on a hard launch (because impacts are more likely to cause damage than the mere transmission of force). You can buy the parts and rebuild it yourself or send it off to a place like TRE. But check the bushings on the diff and subframe, first, since that's easier and cheaper.
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  4. gofer

    gofer Moderator

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    The symptoms you're describing sound like worn carrier bearing(s) or u-joint(s) on the driveshaft.

    :dsm:
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  5. Moonlight GSX

    Moonlight GSX Supporting Member

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    I'll have a look at those, thanks for the help - became concerned. If it is the carrier bearings or u-joints are these expensive to replace? And what would be the level of difficulty for a inexperienced person such as myself to replace these (if they are in fact "bad")?
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  6. mrfister11

    mrfister11 Supporting Member

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    + on u joints.. easy way to check is put car in neutral and get under need with the rear jacked up and spin it back and forth by and watching the u joints.
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  7. gofer

    gofer Moderator

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    JNZTuning: 2g DS Rebuild Kit

    I wouldn't consider it EXPENSIVE to replace, just more of a pain in the butt to do the rebuild/installation of it all. Just be sure that if you do drop the DS and replace the carrier bearings yourself that you mark the alignment of the DS before disassembling it. If you don't, or for whatever reason you marked it wrong, you'll have to take it to someone to get it balanced so it doesn't vibrate like hell. That DS Rebuild Kit that I linked to above DOES NOT include the u-joints, if you want to get those as well (which I suggest since you are tearing apart the DS) call JNZ and ask to include them as well.

    To get an idea of what you'll actually be getting yourself into here is a VFAQ Article on it. 1g DS Rebuild

    :dsm:
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  8. dsmspick

    dsmspick Proven Member

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    Check the three bushings on by your rear differential. My LSD rear end went out from lots of hard launches screwing up those bushings and causing the rear differential to go out. (had chunks of gear and clutch material in it). Juat check all the rubber busing you see for play or cracking or even torn. Oh by the way got my Brembo's on. :) not very hard at all. Have had them on for like 2 weeks with no issues.
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