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  • Crunch!

    Wanted to see if anyone could explain to me why my gearbox crunches into second, doesnt do it in any other gear & if you shift fast enough it doesnt do it at all. When I bought the car the guy I bought it from was waiting on a spring for the gearbox, took months for it to come over here from Japan & when he put it in it still did it. So I made a slight modification to the spring & cut it down a few times to see if it made it any better. It definelty got better the more I did it, but now its sitting level with the gearbox housing & if I cut it anymore then there would be no point in having it there.

    I dont understand whats wrong with it...

    Cheers for your help.



    1985' 2+2 Z31 Non Turbo...
    1986' 2+2 Z31 Turbo...

  • #2
    Synchro?

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    • #3
      What Japanese spring are you talking about :shock:

      The only thing I would think is that your second gear sychro is going out, if not already gone.
      85 Z31 6.0 LSX turbo 766whp/792wtq
      04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

      Comment


      • #4
        WTF is a synchro lol...

        Pretty much wen I take off the top of the gearbox, then the clamp & the rubber boot, theres a spring on the left. That sucker...

        I need to take a pic, but its a lot of work for just one picture lol...



        1985' 2+2 Z31 Non Turbo...
        1986' 2+2 Z31 Turbo...

        Comment


        • #5
          http://en.wikipedia.org/wiki/Manual_tra ... ynchromesh

          Comment


          • #6
            Adman85zx wrote: WTF is a synchro lol...

            Pretty much wen I take off the top of the gearbox, then the clamp & the rubber boot, theres a spring on the left. That sucker...

            I need to take a pic, but its a lot of work for just one picture lol...
            If you did not have synchros in your tranny then every time you shifted to a different gear you would HAVE to match your engine speed with you transmission speed. The sychro acts like a brake to either speed the tranny up when down shifting, or slow the tranny down when up shifting. Sorta.... :roll:

            Oh and it is all the way in the case in your tranny not where the shifter plugs in. I know of no JDM super tuned springs that should go in there. LOL :lol:
            85 Z31 6.0 LSX turbo 766whp/792wtq
            04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

            Comment


            • #7
              Ahhh that makes a lot of sense to me, I had to revv up the engine in the Formula Ford I drove back in a few years to change gears nicely. Cheers.

              My memory is really fucked so I could even be wrong, was a while ago I did this. Ill have to get a picture done.



              1985' 2+2 Z31 Non Turbo...
              1986' 2+2 Z31 Turbo...

              Comment


              • #8
                Nissan calls the synchronizer rings Baulk rings. They are reasonable priced, here in the US anyways. I just got thru rebuilding my T-5 in my 86T and new bearings (4 of them) and baulk rings for 1, 2, and 3. It cost about $100 total.

                1986 300ZX Turbo...sold
                1990 Skyline GT-R...new money pit
                2014 Juke Nismo RS 6-speed...daily

                Comment


                • #9
                  NissanEgg wrote: Nissan calls the synchronizer rings Baulk rings. They are reasonable priced, here in the US anyways. I just got thru rebuilding my T-5 in my 86T and new bearings (4 of them) and baulk rings for 1, 2, and 3. It cost about $100 total.
                  Dont suppose you happened to price all that stuff for a r30a did you?
                  85 Z31 6.0 LSX turbo 766whp/792wtq
                  04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                  Comment


                  • #10
                    I finished rebuilding my r30a about 2 months ago. I used http://www.drivetrain.com for the case bearings and synchros, cost was about $360 then. Bought misc. snap rings and a 2nd gear(don't ask ops: ) for about $120 from http://www.shelbynissan.com They seem to be cheaper than nissanparts and both companies were great to deal with. I don't know if it would actually be cheaper to piece meal the bearings and synchros from shelby nissan.

                    Comment


                    • #11
                      They are actually commonly called blocking/blocker rings, and are part of the synchronizer assembly. They match the speed of the gear to the speed of the dog teeth onto which it is about to engage. I think they commonly wear out prematurely on second gear for two reasons:
                      1-2 is the most common shift the transmission will do in its life, so that blocker ring gets the most use.
                      People using GL5 gear oil, which had additives believed to degrade one of the alloying elements in the nissan blocker rings and hence cause premature wear.

                      I'm not sure what spring would contribute to anything

                      Comment


                      • #12
                        [quote]SATAN wrote:
                        Originally posted by Adman85zx
                        WTF is a synchro lol...

                        Pretty much wen I take off the top of the gearbox, then the clamp & the rubber boot, theres a spring on the left. That sucker...

                        I need to take a pic, but its a lot of work for just one picture lol...
                        If you did not have synchros in your tranny then every time you shifted to a different gear you would HAVE to match your engine speed with you transmission speed.
                        Originally posted by Adman85zx
                        The sychro acts like a brake to either speed the tranny up when down shifting, or slow the tranny down when up shifting. Sorta.... :roll:

                        Oh and it is all the way in the case in your tranny not where the shifter plugs in. I know of no JDM super tuned springs that should go in there. LOL :lol:
                        Yeah, remember when I said that? I said that in the Fidanza flywheel thread too. I dont know what the hell I was thinking. :roll: Listen to Jasons explination. That is the correct one.
                        85 Z31 6.0 LSX turbo 766whp/792wtq
                        04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                        Comment


                        • #13
                          Cant find anything in the service manual about the gearbox. :?



                          1985' 2+2 Z31 Non Turbo...
                          1986' 2+2 Z31 Turbo...

                          Comment


                          • #14
                            Hmm... today I went for a spin, & if I rev the engine slightly & then change gears at the right revvs it goes in smoothly, so it must be the synchro.

                            Wats the fix for this? Hopefully cheap... haha! ops:



                            1985' 2+2 Z31 Non Turbo...
                            1986' 2+2 Z31 Turbo...

                            Comment


                            • #15
                              The fix is taking the tranny apart and replacing the syncro's...and that wont be real cheap.

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