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Do I need a diff rebuild?

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    #16
    Spiders and clutch stack only turn (and make noise) when car is turning; they don't move when car is moving straight.

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      #17
      Originally posted by bigjae46 View Post
      Could also be the spider gears in the diff housing. Or the clutch discs spinning against the steels. At 224k miles it's probably worth a full rebuild. I just rebuilt the diff in my buddy's car...huge difference. It was pretty much an open diff.

      I use Timken bearings and races with OE seals.
      Did you have to adjust the shims with the timken bearings? Did you replace the clutch pack as well?

      Its also 224000 km, thats about 139000 Miles.

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        #18
        To check health of diff clutches:

        Park car in neutral.

        Chock one rear wheel front and back.

        Disengage E brake, wheel chocks ensure car doesnt roll away.

        Jack up opposite side where wheels are chocked.

        Remove wheel center cap to expose axle nut.

        With 32mm (?) socket on a torque wrench measure breakaway torque.


        According to @bigjae healthy torque for healthy diff is between 40-50 lb-ft IIRC. But I would have to double check those numbers.

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          #19
          Ona fresh rebuilt V2 - it was at 116 ft/lbs on the bench. Then fell to 88 ft/lbs after an initial break in drive.

          Before I could spin the wheel by hand.


          Sent from my iPhone using Tapatalk

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            #20
            Originally posted by bigjae46 View Post
            Ona fresh rebuilt V2 - it was at 116 ft/lbs on the bench. Then fell to 88 ft/lbs after an initial break in drive.

            Before I could spin the wheel by hand.


            Sent from my iPhone using Tapatalk
            Thanks for the correction. Another useful thread op should read:

            Hi friends. I didn't have time or tools to dive into a diff rebuild myself, so I got it to a local shop few hours away. (I have few other "spare" diffs I'll dive into later, just timing wise right now is not ideal). Builder sent me first pic, which shows the cap of the v1 unit and a sizable gap, after stacking all

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              #21
              Ill try that this weekend.

              For bearings, I found these on the M3 Cutters UK forum, anyone want t confirm part numbers? Can get Koyos for about 160 CAD from a bearing supplier.

              Outer pinion Bearing/race
              HM89449/HM89410

              Inner pinion Bearing/race
              HM803149/HM803110

              Side bearings and race
              JLM104948/JLM104910

              If I do need a new clutch pack, is my only option aftermarket like racingdiffs or diffs online?

              Comment


                #22
                Originally posted by Lee_Enfield View Post

                Did you have to adjust the shims with the timken bearings? Did you replace the clutch pack as well?

                Its also 224000 km, thats about 139000 Miles.
                I swapped in an extra V2 unit with new clutches and replaced all of the bearings.

                I’m pretty sure the shims are for the case/pinion combo. I haven’t had to mess with changing shins as long as you keep the same exact ring and pinion in the same case.

                Might have to if you swap in a different R&P even if it’s the same ratio.

                Having rebuild three V2 units so far, they are a semi PIA. Wouldn’t recommend it unless you have a really big vise or a press.

                I can rebuild a V1 in about 10-15 min minus any hot washing and cleaning. Super easy.

                Here’s one I just built…












                Sent from my iPhone using Tapatalk

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                  #23
                  Originally posted by bigjae46 View Post

                  I swapped in an extra V2 unit with new clutches and replaced all of the bearings.

                  I’m pretty sure the shims are for the case/pinion combo. I haven’t had to mess with changing shins as long as you keep the same exact ring and pinion in the same case.

                  Might have to if you swap in a different R&P even if it’s the same ratio.

                  Having rebuild three V2 units so far, they are a semi PIA. Wouldn’t recommend it unless you have a really big vise or a press.

                  I can rebuild a V1 in about 10-15 min minus any hot washing and cleaning. Super easy.

                  Here’s one I just built…












                  Sent from my iPhone using Tapatalk
                  You starting a side hustle?

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                    #24
                    Originally posted by eacmen View Post

                    You starting a side hustle?
                    I’ve been working on it. That was for a buddy and I’ve done a couple for locals. Shipping is a PIA. Haven’t had time to figure that out.

                    Cost is $1000 for V1s, $1250 for V2s.


                    Sent from my iPhone using Tapatalk

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                      #25
                      Originally posted by Lee_Enfield View Post
                      Ill try that this weekend.

                      For bearings, I found these on the M3 Cutters UK forum, anyone want t confirm part numbers? Can get Koyos for about 160 CAD from a bearing supplier.

                      Outer pinion Bearing/race
                      HM89449/HM89410

                      Inner pinion Bearing/race
                      HM803149/HM803110

                      Side bearings and race
                      JLM104948/JLM104910

                      If I do need a new clutch pack, is my only option aftermarket like racingdiffs or diffs online?
                      Those are the correct numbers


                      Sent from my iPhone using Tapatalk

                      Comment


                        #26
                        So Finally got around to doing the test mentioned above, and it pretty much free spins. So probably need a new clutch pack.

                        So, where is the best place to get new disks?

                        Looks like I will now be replacing the bearings, clutch pack, all the seals, and might as well throw in a new diff cover since I guess I cannot get new OEM mount bushings by themselves?

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                          #27
                          Originally posted by bigjae46 View Post

                          I’ve been working on it. That was for a buddy and I’ve done a couple for locals. Shipping is a PIA. Haven’t had time to figure that out.

                          Cost is $1000 for V1s, $1250 for V2s.


                          Sent from my iPhone using Tapatalk
                          Wish you lived closer!

                          are you using the racing diffs clutches?

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                            #28
                            Originally posted by tlow98 View Post

                            Wish you lived closer!

                            are you using the racing diffs clutches?
                            Yes


                            Sent from my iPhone using Tapatalk

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                              #29
                              Anyone know the BMW part number for the Pinion crush sleeve?

                              Also, what are my options for OEMish diff bushings apart form a new diff cover?
                              Last edited by Lee_Enfield; 06-09-2022, 09:58 AM.

                              Comment


                                #30
                                Originally posted by Lee_Enfield View Post
                                Also, what are my options for OEMish diff bushings apart form a new diff cover?
                                Not much. Some have used the E36 diff cover bushings but they’re said to be softer and run risk of cracking cover pressing in.
                                I too wish there was the OEM E46 diff cover bushing separately but unaware of anyone yet with that option.
                                6MT SLICKTOP - OE CSL Wheels - OE CSL Brakes - CSL Rack - CSL Trunk - CSL Diffuser - AA Tune - AA Pulleys- AS 40% SSK - 4.10 Motorsport Diff - Bilstein PSS9s - H&R Swaybars - CSL Lip - Gruppe M CF Intake - Supersprint - M Track Mode

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