2nd y u grind?

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  • bimmerboy709
    Advanced Member
    • Oct 2012
    • 100

    #1

    2nd y u grind?

    Hey everyone. The other day I was driving quite spirited for a few minutes on my way to a buddies house up the street. Once I left his house I noticed 2nd gear was making a crazy whine and there was rattling coming from the trans. Almost sounded like a dog box on steroids.

    Anyways, the next day I asked my auto shop teacher if I could bring it in to service the trans. He approved so a friend of mine and I lifted her up and changed the fluid hoping it would make a difference. We had noticed the fluid was pretty burnt and was actually quite low. Maybe only about half a liter of nasty black old trans fluid dripped out. We filled it back up with just over a liter of what my auto shop instructor said was 75w-80 gear oil.

    I took the car out once class had finished to leave.

    1st was a little stiff to get into. I shifted to 2nd at about 2700 and it grinded pretty hard but the whine was gone. all gears after that went smoothly.

    Now, 3 days later, it does not grind as often going into 2nd if I shift just right or the car is at operating temp; However, it does grind no matter what when rev match downshifting so I've stopped doing that to get as much out of the current trans as possible.. lol.

    A buddy of mine recommended it was either a bearing or a syncro gone bad. Either way I'm just going to pick up a new getrag260 but I'm just curious of what went wrong. I hope to try and remove the bellhousing and take a deeper look after I get the new trans in to see what had gone wrong.

    What do you guys think?
    ERHMAGHERD! BERMER!
  • ButtJuice
    R3VLimited
    • Dec 2009
    • 2609

    #2
    Syncro went bad probably.
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    • Northern
      R3V Elite
      • Nov 2010
      • 5040

      #3
      My mazda does this... and its 20 years newer than my newest e30. What a piece of crap.
      Originally posted by priapism
      My girl don't know shit, but she bakes a mean cupcake.
      Originally posted by shameson
      Usually it's best not to know how much money you have into your e30

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      • rubicon express
        Noobie
        • Feb 2013
        • 2

        #4
        It deffinately sounds like a synchro.
        I have a weak synchro last longer when you put good quality synthetic oil in the gear box. It should help it shift easier too.

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        • LJ851
          R3V OG
          • Nov 2010
          • 7918

          #5
          1) Dog engagement doesn't make noise, straight cut gears make noise.

          2) If you are rev matching and grinding on downshifts you are doing it wrong.

          3) It takes some serious work to get manual transmission oil to burn, congratulations on the effort!

          4) Sounds like your syncro(s) are shot and probably more, you are on the right track looking for another gearbox.
          Lorin


          Originally posted by slammin.e28
          The M30 is God's engine.

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          • ser1992
            E30 Addict
            • Feb 2013
            • 482

            #6
            "it does grind no matter what when rev match downshifting"

            You say the world "match", but I dont think you mean it. You should be able to rev-match downshift on a car without syncros at all and it will not grind.. because they will be rpm matched...

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            • ELVA164
              R3V Elite
              • Dec 2011
              • 4861

              #7
              Sounds to me like running the gearbox with too little oil accelerated the wear on the synchro and possibly smoked a bearing. Second gear always gets the hardest workout in any manual gearbox, which is why most of our second gear synchros are worn at this point. If it is just the synchro, you can work around it. Allow the car to warm up a little on very cold days, double clutch on EVERY shift until the car is at operating temperature (middle of the gauge), and even avoid second gear until the car has warmed up a bit. Whatever you do, don't try to shove it in if it is grinding or resisting. You'll just be accelerating its demise.
              Interested in vintage cars? Ever thought about racing one? Info, photos, videos, and more can be found at www.michaelsvintageracing.com!

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              • e30Rooster
                E30 Modder
                • Jan 2010
                • 958

                #8
                I love rev matching

                Sent from my C771 using Tapatalk 2
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