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Ideas on adding reverse lockout to KA tranny?

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  • Ideas on adding reverse lockout to KA tranny?

    So in the last year I've stripped the teeth of 3 KA trans from missing my 3-4 shift and hitting reverse. I blame some of this on soft engine mounts and some of it on bad driving.

    The problem still stands-- I keep hitting reverse during races and knocking the teeth off. Since reverse is the LAST gear to come off the shaft, this makes a simple rebuild to replace it much more difficult, and the cost to replace it is more than the cost of another junkyard trans.

    Any ideas on how to add a lockout to the stock trans so I can eliminate this problem at the source?
    Originally posted by SoSideways
    I don't care what color they are as long as they are LONG AND HARD.
    '04 G35 Sedan 6MT- The DD
    '96 240SX- The Track Toy

  • #2
    Why not just add a plate that can flip down over the reverse gate on a hinge, then when you are in the paddock and might need reverse, you flip it up and go. Out on track you fasten it down with a spring or something.
    '18 Chevrolet Volt - Electric fun hatch for DD duty!


    DefSport Koni Sleeve and Spring Perch Buy!!!
    http://www.nissanroadracing.com/showthread.php?t=5902

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    • #3
      Or replace the motor mounts, if that's a contributing factor?

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      • #4
        I replaced the motor mounts last week w/ JGS mounts that are nearly solid. I still missed a shift during the race, but it was only once. (I have nobody to blame but me on that one).

        Def, that's basically what I'm trying to figure out how to do-- can't attach to the body since the trans moves independent of the chassis (and this is some of the problem..) I'm trying to think of a way to attach this gizmo to the back of the transmission- maybe through a few of the 6 bolts on the shifter plate and bring it through the hole in the trans tunnel.
        Unfortunately I'm having a hard time picturing how that would work.

        I have 3 dead trans sitting in the garage. I guess it's time to grab one and start playing with it.

        Another thought was an electric solenoid I can mount to the case near the shift linkage that would take a pushbutton to engage or something.
        Originally posted by SoSideways
        I don't care what color they are as long as they are LONG AND HARD.
        '04 G35 Sedan 6MT- The DD
        '96 240SX- The Track Toy

        Comment


        • #5
          If the trans is moving enough that your gates are changing their position that much, then I think that's your problem.

          I don't see a problem with putting the lockout on the chassis. The relative motion shouldn't be that much. Obviously you don't want it right against the 4th gear gate, but if you give yourself a little clearance and it's still moving around and fouling into stuff, then you need to keep the engine/trans more steady.


          If you want to put it on the trans just put a few pop rivets on a stiffener rib and run some ~16 ga steel up there and a piano hinge section. Should be plenty for a reverse lockout.
          '18 Chevrolet Volt - Electric fun hatch for DD duty!


          DefSport Koni Sleeve and Spring Perch Buy!!!
          http://www.nissanroadracing.com/showthread.php?t=5902

          Comment


          • #6
            Are you using a short shifter? After I installed mine the return to neutral was a lot more authoritative and required more effort to move the shifter side to side (1-2 and 5-r gates). maybe that will help if you're using stock shifter?

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            • #7
              You could also replace the 2 centering springs in the shifter with stiffer or maybe just newer ones. Had that idea a while back to make 2-3 shifts easier (very much fear a 2-1 upshift). Haven't done it yet but it's simple enough to explore.

              Edit: Apparently Circuit Sports sells a return spring kit.
              Sent from my XT907 using Tapatalk

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              • #8
                Originally posted by AceInHole View Post
                You could also replace the 2 centering springs in the shifter with stiffer or maybe just newer ones. Had that idea a while back to make 2-3 shifts easier (very much fear a 2-1 upshift). Haven't done it yet but it's simple enough to explore.

                Edit: Apparently Circuit Sports sells a return spring kit.
                Sent from my XT907 using Tapatalk
                Gktech also sells one.

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                • #9
                  a 2-1 shift shouldn't be a problem on this car, mainly because there's so few tracks I need 2nd gear. I've done 5-2 a couple times at ~100mph, but that was just an oops..

                  My main problem is 3-R. and yes, with the stock KA engine mounts, the movement can be measured in inches, not fractions or mm... It was enough movement that my shifter would move >2" if I hit the rev limiter. Since I shift at ~6700rpm, I quite often just barely bump the rev limiter in 3rd before a shift, and this is when the problem happens.. The engine is bucking and the gates are so sloppy on these trans that it's easy to hit the wrong gear when your trans has moved 2" in a random direction!

                  With the new engine and trans mounts, it's a lot better but I still want to see how much they're moving on a video or something before I fab something to the chassis instead of the trans.

                  The problem with mounting it to the trans is I now have no shifter boot to protect my arm from fire should the engine let go and shoot burning oil down the trans tunnel. I'm not worried about going up in a ball of flames, but I also don't want to invite trouble for myself.

                  If I mount it to the trans tunnel, I can solve that problem but then I invite the problem of the thing possibly not working or doing other things it shouldn't.
                  Originally posted by SoSideways
                  I don't care what color they are as long as they are LONG AND HARD.
                  '04 G35 Sedan 6MT- The DD
                  '96 240SX- The Track Toy

                  Comment


                  • #10
                    I think going to heavier centering springs should help you find 4th, and also take out a lot of the slop in the 3-4 gate.

                    Sent from my XT907 using Tapatalk

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                    • #11
                      It's not finding 4th that's the problem.. it's the finding reverse that's the problem!! But yes, I agree. stiffer springs are definitely worth a shot and much easier than the other stuff.. Wonder if there's enough in the tunnel room to pull those springs out with the trans installed? I've pulled the trans after every race for the last 6 months. ugh.
                      Originally posted by SoSideways
                      I don't care what color they are as long as they are LONG AND HARD.
                      '04 G35 Sedan 6MT- The DD
                      '96 240SX- The Track Toy

                      Comment


                      • #12
                        I think you can get to everything with the trans in the car.

                        http://www.gktech.com/index.php/sr20...pring-kit.html

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                        • #13
                          Yeah I think I can.. the springs aren't that long. not sure if I want to pay $50 for a couple springs tho. Then again, I can spend hours designing, building, and installing a $5 part...
                          Originally posted by SoSideways
                          I don't care what color they are as long as they are LONG AND HARD.
                          '04 G35 Sedan 6MT- The DD
                          '96 240SX- The Track Toy

                          Comment


                          • #14
                            Nissanparts.cc and enjuku both carry gktech stuff, though i think the prices aren't any better than what you pay direct :-/

                            Comment


                            • #15
                              Why don't you try a B&M knockoff shifter? They have return springs in the linkage, so that the feel is actually decent with those + OEM return springs.
                              '18 Chevrolet Volt - Electric fun hatch for DD duty!


                              DefSport Koni Sleeve and Spring Perch Buy!!!
                              http://www.nissanroadracing.com/showthread.php?t=5902

                              Comment

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