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    DSS one piece driveshaft vibration

    I am fresh out of ideas and patience with my E30. It's had driveshaft issues for a while and I can't figure it out. Any help would be greatly appreciated and keep me from setting it on fire.

    It vibrates pretty bad past 70 mph and only gets worse as speed increases. It's speed dependent and nothing to do with engine; trans in neutral and vibration doesn't change.

    The backstory: I got a junkyard 87+ eta trans a year ago with some issues I didn't realize at the time. I think the output shaft was a little bent from the getgo. I also got a serviceable driveshaft from an E30 parts shop for cheap, which ended up being imbalanced and having junk ujoints. I replaced the ujoints and had the shaft balanced. Still vibrated pretty bad, but the trans output shaft was visibly bent by this point. I broke the giubo bolts at least 5 or 6 times before the trans bearings started screaming under boost. I got a one piece driveshaft from driveshaft shop and had to space the diff off the subframe with the oem washers to get the diff adapter to clear. Driveshaft vibrated at 70+ mph, so I took another look. While I was at it, I replaced the diff and transmission with fresh ones that had no issues. The car shifts great and there's no more noise or excessive lash in everything. However, the driveshaft vibrates pretty bad at 70+ still.
    I tried rotating it 180 degrees and rebolting it to the rear adapter and spacing the diff with a second set of washers just in case the driveshaft ever moved enough to hit the subframe.
    In theory, the bushings and washers would only move the diff vertically and retain the alignment with the transmission, so the angles would be complementary.

    I checked the motor and trans mounts and they seem fine. Poly motor mounts with maybe 8k miles on them. Rubber oem trans mounts that look good. I have lifted the motor and let it set a couple times with the mount bolts loose to swap oil pump and relief valve, but I didn't see any alignment dowels on them, just solid poly cylinder with a bolt in the center.

    With the original driveshaft, I had the car up to 140 before and had no vibration. Now, I'm worried to take drive take it up to 70. Is there something I'm missing?

    #2
    Originally posted by mohmoh62 View Post
    I am fresh out of ideas and patience with my E30. It's had driveshaft issues for a while and I can't figure it out. Any help would be greatly appreciated and keep me from setting it on fire.

    It vibrates pretty bad past 70 mph and only gets worse as speed increases. It's speed dependent and nothing to do with engine; trans in neutral and vibration doesn't change.

    The backstory: I got a junkyard 87+ eta trans a year ago with some issues I didn't realize at the time. I think the output shaft was a little bent from the getgo. I also got a serviceable driveshaft from an E30 parts shop for cheap, which ended up being imbalanced and having junk ujoints. I replaced the ujoints and had the shaft balanced. Still vibrated pretty bad, but the trans output shaft was visibly bent by this point. I broke the giubo bolts at least 5 or 6 times before the trans bearings started screaming under boost. I got a one piece driveshaft from driveshaft shop and had to space the diff off the subframe with the oem washers to get the diff adapter to clear. Driveshaft vibrated at 70+ mph, so I took another look. While I was at it, I replaced the diff and transmission with fresh ones that had no issues. The car shifts great and there's no more noise or excessive lash in everything. However, the driveshaft vibrates pretty bad at 70+ still.
    I tried rotating it 180 degrees and rebolting it to the rear adapter and spacing the diff with a second set of washers just in case the driveshaft ever moved enough to hit the subframe.
    In theory, the bushings and washers would only move the diff vertically and retain the alignment with the transmission, so the angles would be complementary.

    I checked the motor and trans mounts and they seem fine. Poly motor mounts with maybe 8k miles on them. Rubber oem trans mounts that look good. I have lifted the motor and let it set a couple times with the mount bolts loose to swap oil pump and relief valve, but I didn't see any alignment dowels on them, just solid poly cylinder with a bolt in the center.

    With the original driveshaft, I had the car up to 140 before and had no vibration. Now, I'm worried to take drive take it up to 70. Is there something I'm missing?


    Tldr?
    ACS S3 Build / Dinan 5 E34

    Comment


      #3
      Originally posted by TimeMachinE30 View Post
      Tldr?
      Figured I should be thorough. tldr driveshaft vibrates for no reason. Help me.

      Comment


        #4
        Seems you have changed loads of variables so you are way off OEM specs.

        Have you taken the car back to who made the 1 piece driveshaft with it installed and got them to have a look at your setup?

        Comment


          #5
          Originally posted by e30davie View Post
          Seems you have changed loads of variables so you are way off OEM specs.

          Have you taken the car back to who made the 1 piece driveshaft with it installed and got them to have a look at your setup?
          I ordered it from DSS.

          I live 12+ hours away.

          They said to try rotating it 180 degrees. Didn't help. Said they'd recheck balance if I sent it back, which I intend to do, but I don't think that's the issue. Rotating it with respect to the adapters should've caused the frequency to change. The variables should do nothing to the alignment of the transmission and differential. As long as they're parallel, it shouldn't matter. I guess that's what I'm asking; is there something that could be causing the alignment to be off that I'm not aware of? Or any other ideas?

          Comment


            #6
            Bad transmission or motor mounts could affect alignment, as could a damaged subframe.
            The car makes it possible, but the driver makes it happen.
            Jim Levie, Huntsville, AL

            Comment


              #7
              Originally posted by mohmoh62 View Post
              I ordered it from DSS.

              I live 12+ hours away.

              They said to try rotating it 180 degrees. Didn't help. Said they'd recheck balance if I sent it back, which I intend to do, but I don't think that's the issue. Rotating it with respect to the adapters should've caused the frequency to change. The variables should do nothing to the alignment of the transmission and differential. As long as they're parallel, it shouldn't matter. I guess that's what I'm asking; is there something that could be causing the alignment to be off that I'm not aware of? Or any other ideas?


              One piece driveshafts like equal and opposed angles in one plane only. If you have angles in two planes that very possibly could cause your situation.

              An E30 drivetrain from crank to diff input is straight and sits in the car at an angle left to right. The front of the crank is biased toward the drivers side and the diff input is biased towards the passengers side. The driveshaft hits the diff at an angle horizontally.

              Rotating the engine and trans assembly on the horizontal plane should allow you to get equal and opposed angles in the horizontal plane , but raising the diff straight up would introduce compound angles which could vibrate.

              The only way to eliminate a horizontal angle would be to rotate the diff horizontally so the input pointed directly at the tail of the trans, which it does not do from the factory.


              The factory 2 piece driveshaft is extremely forgiving....
              Lorin


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

              Comment


                #8
                Have you checked the diff input flanges carefully to make sure they're not bent?
                (I noted you used 2 different diffs)
                I've chased my ass on those more than once.
                It doesn't take more than a few thou of runout to cause problems, and it's pretty easy
                to bend a flange when the diff's floating around loose.

                Other than that and the trans flange and pilot nose... I got very little...

                t
                now, sometimes I just mess with people. It's more entertaining that way. george graves

                Comment


                  #9
                  Well. The subframe bushings were upside down. The spacing I put in there for the diff was supposed to bring it back to oem alignment with trans. Instead it was putting it even lower. I pulled the rear subframe after work and am going to flip those bushings, maybe do some cleanup on everything. I would imagine this has caused all the problems the past couple years. Just never really noticed til the one piece went in.

                  Comment


                    #10
                    Originally posted by mohmoh62 View Post
                    Well. The subframe bushings were upside down. The spacing I put in there for the diff was supposed to bring it back to oem alignment with trans. Instead it was putting it even lower. I pulled the rear subframe after work and am going to flip those bushings, maybe do some cleanup on everything. I would imagine this has caused all the problems the past couple years. Just never really noticed til the one piece went in.
                    Nope. New diff bushings, new subframe bushings, no change. It starts vibrating bad around 90.

                    Comment


                      #11
                      sounds like the solution to all your problems is to put the diff back in the stock location and buy a

                      bmw 2 piece driveshaft

                      new u joints

                      center support bearing

                      new guibo


                      -
                      Project
                      Parts for Sale
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                      Comment


                        #12
                        I've heard these causing vibrations.

                        Can you put the stock one back in?

                        I was up above it, Now I'm down in it ~ Entropy - A Build thread.
                        @Zakspeed_US

                        Comment


                          #13
                          I got the one piece because I broke the stock one. It's pushing somewhere around 350-400 at the crank.

                          More to this story. I swapped rubber motor and trans mounts in and reinforced the subframe. DSS agreed to rebuild it with a CV joint. They got the measurements wrong the first time for some reason and I had to send it back because the CV eliminates the slider... Has to be exact length to ~1/2". Dropped the second one in and it vibrates at higher speed now. Becomes very noticeable at 80, really bad at 100; didn't want to go any higher. I've asked for a refund but who knows at this point. In the past two years I've put maybe 200 miles on it because of this issue. If they decide to refund me I'm putting the stock one back in for a while. If not, I'm stuck with a $1000 paper weight.

                          Comment


                            #14
                            The basic solution to your problem was was back in 2017:
                            Originally posted by LJ851 View Post
                            One piece driveshafts like equal and opposed angles in one plane only. If you have angles in two planes that very possibly could cause your situation.

                            An E30 drivetrain from crank to diff input is straight and sits in the car at an angle left to right. The front of the crank is biased toward the drivers side and the diff input is biased towards the passengers side. The driveshaft hits the diff at an angle horizontally.

                            Rotating the engine and trans assembly on the horizontal plane should allow you to get equal and opposed angles in the horizontal plane , but raising the diff straight up would introduce compound angles which could vibrate.

                            The only way to eliminate a horizontal angle would be to rotate the diff horizontally so the input pointed directly at the tail of the trans, which it does not do from the factory.


                            The factory 2 piece driveshaft is extremely forgiving....

                            I have a 1 piece driveshaft in my race car because I went to a T5 transmission.
                            I had loads of vibration issues until we sorted out the equal and opposing angles.
                            There is not much realistically you can do to the clocking described above in the quote, but you can mitigate it alot by shimming the diff angle vs trans output shaft angle to make those equal and opposing in the vertical plane.
                            Mine is now happy to top of high gear, I can feel just the slightest hint of vibration at high speed in 5th gear just oncoming, but its nothing even remotely like it was.
                            Jimmy P.
                            87 E30 M3 Prodrive British Touring Car
                            88 E30 M3 Zinnoberot - Garage Queen
                            88 E30 M3 Lachsilber - SCCA SPU #98
                            92 M Technic Cabrio - S14 Powered!
                            98 318Ti Morea Green
                            04 Ford F350 Dually Tow Machine

                            Comment


                              #15
                              Originally posted by mohmoh62 View Post
                              I got the one piece because I broke the stock one. It's pushing somewhere around 350-400 at the crank.



                              More to this story. I swapped rubber motor and trans mounts in and reinforced the subframe. DSS agreed to rebuild it with a CV joint. They got the measurements wrong the first time for some reason and I had to send it back because the CV eliminates the slider... Has to be exact length to ~1/2". Dropped the second one in and it vibrates at higher speed now. Becomes very noticeable at 80, really bad at 100; didn't want to go any higher. I've asked for a refund but who knows at this point. In the past two years I've put maybe 200 miles on it because of this issue. If they decide to refund me I'm putting the stock one back in for a while. If not, I'm stuck with a $1000 paper weight.


                              Solution to problems is:

                              Install Oem Bmw 2 piece driveshaft.

                              350-400hp is not a problem.
                              OBD1 M54/M52TU swap as a M50b25

                              Z4 non powered steering rack fits e30



                              Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

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