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shuddering/banging/thumping under hard acceleration/torque - I'm stumped - HELP

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    #1

    shuddering/banging/thumping under hard acceleration/torque - I'm stumped - HELP

    1989 325i s52 swapped with g260 trans, JBR 11lb flywheel, 3.23 LSD

    While driving home about 3 miles from home I accelerated from a turn and felt a shuddering/bumping as if I was driving over a bunch of tiny bumps. It was weird, so after next light, I accelerated hard again and felt the same thing happen. It can be felt through the seat and through the shifter. It almost sounded like the driveshaft was banging around. I drove home carefully and paid close attention. I could ever so slightly feel this as I drove in other gears, but not even close to how bad it is under hard acceleration and torque. I could only recreate the problem in 1st and 2nd.

    I was planning to do a bunch of work on it anyway, so I started taking stuff apart to see if I could notice anything obvious.

    -took cover off diff and drained fluid; it looked normal
    -removed 2nd half of driveshaft to inspect U joint; it looked normal
    -the CSB is new, but looked normal
    -half shafts looked normal (I also just replaced one and rebuilt the other)
    -wheel bearings seemed fine as far as I could tell? (no play when shaking the tire on an angle)
    -guibo looks fine (probably could be replaced, but didn't seem to be an issue)

    Also, all suspension bushings are new, coilovers are new, tires are new, brakes are new, and the engine was just entirely rebuilt (by me :) )

    So needless to say, I am totally stumped on this one.
    '89 325i OBD2 S52 BUILD THREAD
    Shadetree30

    Tags: None
    #2
    Make sure the driveshaft halves are aligned. It's hard to see damage on the guibo unless you remove it.

    Comment

      #3
      Originally posted by vpilarrt View Post
      Make sure the driveshaft halves are aligned. It's hard to see damage on the guibo unless you remove it.
      They are aligned. The car was driving perfectly fine for a few months, this issue just popped up suddenly.

      I am doubting it's the guibo. THe symptoms don't match a failing/failed guibo (I've killed one in my e36). Starting to suspect the DS U joints after some googling. Seems to be a "common" high mileage failure.
      '89 325i OBD2 S52 BUILD THREAD
      Shadetree30

      Comment

        #4
        Originally posted by Sh3rpak!ng View Post
        They are aligned. The car was driving perfectly fine for a few months, this issue just popped up suddenly.

        I am doubting it's the guibo. THe symptoms don't match a failing/failed guibo (I've killed one in my e36). Starting to suspect the DS U joints after some googling. Seems to be a "common" high mileage failure.
        This is EXACTLY what happened in my gf's e30. The giubo failed after several months of poor driveshaft alignment.
        It came on suddenly, and was pronounced when accelerating in 1st and 2nd.

        Comment

          #5
          I just did a guibo & csb & am still dealing with a driveline vibration. I am leaning towards the diff mount bushing

          Comment

            #6
            Well what I've read is that CSB failure is usually the result of u joint failure or other DS alignment issues. I just replaced the CSB because it was totally torn up.


            Sent from my iPhone using Tapatalk
            '89 325i OBD2 S52 BUILD THREAD
            Shadetree30

            Comment

              #7
              Originally posted by TravisAsch View Post
              I just did a guibo & csb & am still dealing with a driveline vibration. I am leaning towards the diff mount bushing
              Not sure that's it. I replaced mine thinking the same thing and it changed nothing. And the original bushing was shot.

              Again, should've googled first, but I am suspecting the U-joints. From what I've found from googling, most of these driveline vibration problems are rooted in bad U-joints which cause the CSB/guibo to wear out.
              '89 325i OBD2 S52 BUILD THREAD
              Shadetree30

              Comment

                #8
                If it's NOT the u- joints, it might be the LSD itself- when the clutches weld up, or have
                the wrong fluid, they can skip or bind/release... hope it's not that....

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

                Comment

                  #9
                  Originally posted by TobyB View Post
                  If it's NOT the u- joints, it might be the LSD itself- when the clutches weld up, or have
                  the wrong fluid, they can skip or bind/release... hope it's not that....

                  t
                  I don't think so, but I could be wrong. The fluid was clean when I drained it (it was only 6 weeks old). Using the correct fluid (redline 57904 75w-90). And I cobbled the diff together (e30 3.23 case with an e36 LSD unit) and the LSD unit was known good and working from a friend's car. Either way, it's out of the car, drained, and apart so I guess now would be the time to replace the clutches and dog eared plates.... $$$
                  '89 325i OBD2 S52 BUILD THREAD
                  Shadetree30

                  Comment

                    #10
                    When you put torque on the system as you accelerate, things move around a bit. Is anything in close proximity to the guibo nuts or bolts? The flutter could be due to flex on engine or trans mounts shifting the drive train enough to hit on something. Check for light wear marks where the bolts hit on the back of the transmission or anything else in that neighborhood. What motor and trans mounts did you use?

                    Comment

                      #11
                      Originally posted by ahlem View Post
                      When you put torque on the system as you accelerate, things move around a bit. Is anything in close proximity to the guibo nuts or bolts? The flutter could be due to flex on engine or trans mounts shifting the drive train enough to hit on something. Check for light wear marks where the bolts hit on the back of the transmission or anything else in that neighborhood. What motor and trans mounts did you use?
                      Good suggestion. I'll check tightness on all the mounts. Though I have my doubts, it can't hurt. Just replaced the rear output seal on the trans and tightened all that stuff up again.

                      Mounts are all brand new (~2 months), they went in with the new motor. Revshift green poly swap mounts and condor uhmw trans mounts.
                      '89 325i OBD2 S52 BUILD THREAD
                      Shadetree30

                      Comment

                        #12
                        Check your engine and trans mounts. Sounds like you could have some failed ones.

                        Comment

                          #13
                          Originally posted by CorvallisBMW View Post
                          Check your engine and trans mounts. Sounds like you could have some failed ones.
                          Doesn't make sense (because they're brand new), but I will.
                          '89 325i OBD2 S52 BUILD THREAD
                          Shadetree30

                          Comment

                            #14
                            Oops, didn't see that part. disregard.

                            Comment

                              #15
                              I had very similar issues and it was the u joints. Driveshafts aren't that expensive anymore, thankfully.

                              Comment

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