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Need opinions on noise from transmission *video included

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  • Need opinions on noise from transmission *video included

    Hey guys,

    So I got this rattle going on from my transmission whenever I am not pressing the clutch in. Id like to hear your opinions on the sound. I am leaning towards release bearing, but I plan to replace all clutch related parts regardless.

    Ignore the radio and my blabbering for the first part. The clutch was squeaky when I made the video, but that sound has since gone away. Only concerned with the sound once the motor starts.
    https://www.flickr.com/photos/103594...5/16824292700/

  • #2
    I should also note that the sound gets worse as the car warms up.

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    • #3
      Mine makes a similar noise but not as loud...I've been told that it might be the input shaft bearing or throw out bearing? Haven't really gone anywhere to have it checked! Please let me know if you find out what the cause is.

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      • #4
        Without hearing the video, I am going to say layshaft bearings in the tranny. Google "GETRAG Rattle"
        It's very very common.

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        • #5
          I am aware the getrags are known to be noisy, but I heard this noise last fall and its noticeably worse this spring.

          I am first going to replace the transmission fluid to see if that has any effect on the noise. Then I will proceed to replace the clutch, pressure plate, release bearing, pilot bearing, etc. if nothing changes.

          Also worth noting, my car is noticeably shaky as well.

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          • #6
            Shaky would not be the tranny. Maybe a pressure plate strap snapped? Doubtful if it drives ok. Typically with the getrag rattle, and I have had it in two separate transmissions on my m3, it's quiet when cold as the fluid is thicker. As the car warms, the fluid thins and the noise is more noticeable. Try a heavier fluid maybe?

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            • #7
              I cannot play your video...wants me to sign up or something.

              Getrags, even in perfect condition, tend to be noisy while idling with the clutch released. This is especially noticeable with lightweight flywheels, stiff motor/tranny mounts, and low viscosity gear oil. The "normal" noise is kind of hard to describe, but is sort of a clattery rattle. If you push in the clutch, the noise stops because the input shaft in the tranny is no longer spinning.

              My car has a chrome-moly flywheel that is very thin, so I have the added delight at idle of a slight ringing noise.

              So without hearing your car, it is hard to say....but I think there is a good chance what you are hearing is normal Getrag clatter.
              Last edited by Ironhead; 04-07-2015, 04:41 PM.

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              • #8
                Todd, my friend who is helping me with the work also brought up the idea of a pressure plate strap breaking as to why the car shakes. And a heavier fluid will be added before I go ahead and take the transmission out, just to see if it makes any difference.

                Ironhead, sorry, I wish I knew how to embed it here. But what makes me think its not normal is the fact that the noise is noticeably worse than it was when I put the car away.

                Appreciate the replies.

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                • #9
                  I too have the very exact chatter , i do have lightened fly wheel as well so maybe that adds to it. I bought the car with 165k on it and it now has 233k and i have beat the snot out of the car with zero issues out of the transmission (actually no problems with the drive train whatsoever). Todd black 88 , you mentioned a thicker fluid ? What type of fluid do you guys recommend ??

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                  • #10
                    Unfortunately in my opinion, your gearbox is just about ready for a re build. Yes its normal to have a chatter with these even after they have been re built, but thats quite bad. Shortly after mine sounded like that, it started to make noises that you could clearly hear while driving. If your doing a clutch, just re build the box.
                    James

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                    • #11
                      I managed to get your video to play....

                      It "sounds" like normal Getrag clatter to me...at least in terms of the type of noise. What is difficult to judge from the video is how loud/extreme it is relative to other Getrags I have heard. I'm inclined to think that if you have a stock flywheel, the noise sounds like a bit more than it should. If you have a lightweight flywheel, probably not. One of the things a heavy flywheel does is dampen the noise from input shaft clatter.

                      I know you say it's louder than it used to be, but are you sure? The reason I ask, is E30M3s are by their nature kind of noisy cars with lots of mechanical whirs, rattles, and clicks. I find if I haven't driven mine for a while, my perceptions about what it "should" sound like are all out of whack. Could that be what is going on with yours?

                      I also sort of wonder because I have not heard of too many instances of the input shaft bearings going out on 265 Getrags. When they need rebuilds it is usually because of dead synchros.

                      I noticed an oil spot under your car....are you sure the tranny is filled to capacity? I am currently using Redline Lightweight Shockproof gear oil in my tranny, and with that I noticed significantly less chatter than with MTL. You might give that a try and just see how it sounds.

                      I am suggesting all this because a proper Getrag rebuild is very expensive, not to mention finding a place you trust to do it and (probably) shipping the tranny there. I would hate to see you do all that if not needed.

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                      • #12
                        Originally posted by Ironhead View Post
                        I managed to get your video to play....


                        I also sort of wonder because I have not heard of too many instances of the input shaft bearings going out on 265 Getrags. When they need rebuilds it is usually because of dead synchros.

                        I noticed an oil spot under your car....are you sure the tranny is filled to capacity? I am currently using Redline Lightweight Shockproof gear oil in my tranny, and with that I noticed significantly less chatter than with MTL. You might give that a try and just see how it sounds.

                        I am suggesting all this because a proper Getrag rebuild is very expensive, not to mention finding a place you trust to do it and (probably) shipping the tranny there. I would hate to see you do all that if not needed.
                        Well in my case, the bearings were shot but the synscros were fine. I had mine re built about 6 years ago by a Getrag specialist and it was about $450 over here, but I could still hear the chatter, although very slight even with brand new bearings. I'm starting to hear it again now though, so your comment about oil interests me.
                        James

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                        • #13
                          I agree it is Getrag rattle. I had the same problem. and figured it was because the previous owner put redline shockproof oil in it. I switch it out for some good old fashion dino oil. I think I used 85W-140 and the rattle is gone. One thing to note is that the thicker oil might make it more difficult to shift depending on your tranny's health fortunately for me I did not have that problem.

                          From what i understand the rattle is the unloaded bearings rattling while the car is in neutral. It then makes sense that a higher oil film thickness would reduce the vibration

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                          • #14
                            Thanks for all the replies. I am hoping the transmission does not need to be rebuilt, and that will be a last resort.

                            I plan to put mt90 in hopefully by this weekend to see if that makes any difference.

                            Ironhead: Thank you for your thoughts. The puddle of fluid under my car is from a bad high pressure PS line, but that thought has crossed my mind as well. Which is why I am swapping redline mt90 in before I start taking anything apart.

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                            • #15
                              I'll add that it doesn't sound all too terrible to me, either.
                              But do monitor it for changes in sound. As mentioned, oil choice can play a role in the noise output.

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