dodged a bullet.

Discussion in 'Modifications & DIY how-to' started by crash#2, Oct 9, 2006.

  1. crash#2

    crash#2 Member

    been searching for a while now trying to find out why my tranny has a grinding sound on decel in 3rd gear. i thought "oh sh!t time to spend some mulla" but apparently that shakey sound can be fixed. see i installed a kartboy ss and bushings the day before i had a stronger clutch installed, here i thought that the clutch did it. well this guys discovery is pretty neat.
    got this off of nasioc. "Well i've had a twm short shift installed for a long time, and the added NVH was really starting to get to me. over the months i tried alot of things, such as grinding the metal plate for more clearence, adding weight to the shifter, dynamat etc. they helped, but nothing got rid of the 4000 RPM vibration.

    all this time, i was pretty sure it was because the twm SS is not potted with rubber like the OEM one, so i decided to modify my OEM shifter into an SS while retaining all the weight and rubber. i did so succesfully, but upon my first test drive, the NVH was still there

    so i started researching a bit, and i realised that most people say the full STi short shift linkage doesnt have any vibration problems. but when you look at the shifter included, its got no rubber potting, its a simple steel rod. so it cant be because of that. upon further inspection, i realised there is only one significant difference between the STi linkage and my OEM one, the shift fork is more bent! (yeah so thats all you get for 250$, an extra bend)

    looking under the car, i realised that because the short shifter raises the height of the shift fork, it causes the clearance between it and the under chasis to be almost none. but the STi having a bend in it, increases the clearance.

    so i took apart my linkage (with much grief! urgh i hate that u-joint) and took a big hammer and bent my shift fork a lil less than an inch, reinstalled it (with lots more swearing) and voila! no vibration whatsoever. couldnt be happier.


    MOD DETAILS:
    i basically bent rod (A) in the picture so that it curves more upwards. the part that rubbed was on the top side of the rubber boot on rod (A). by bending it, the rod can pass horizontally near the underbody, instead of angling right away upwards as before. this is because the connection with the shifter is located higher with a short shifter."

    i think it might be too time consuming to do anytime soon though.
     
  2. calmnothing

    calmnothing Shlimp Flied Lice Supporting Member

    Yep! This is an old trick I learned on the RS boards. I have yet to try it yet because I'm too lazy to take apart my linkage.
     
  3. crash#2

    crash#2 Member

    me too!
     
  4. GTscoob

    GTscoob Black is Beautiful

    I'd say I'd like to see how it feels compared to my STI shifter but I really have no desire to drive your car with the 6puck on it.
     
  5. crash#2

    crash#2 Member

    aw common it's fun!
     

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