Upgrades for 02A/ J/ C gearboxes

Discussion in 'Transmission' started by Isaac Pettit, Jan 26, 2018.

  1. Isaac Pettit

    Isaac Pettit Paid Member Paid Member

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    Hello,

    There aren't too many things you can do to strengthen this generation of gearbox, but I'll be building as strong an 02C as I can manage and wanted to post up the modifications I'm doing to it for anyone else who might be interested. Also hope to hear ideas from others who've done similar things.

    My apologies if this is so obvious that this won't be a helpful thread. I've been searching and wasn't able to find a concise list so thought in the off chance someone else would also some day I'd put one together..

    1. Aftermarket gearkit: Most companies that make gear kits offer dog or helical type in a variety of different ratios.
    SQS: http://www.sqsracing.com/kategorie-produktu/23:competition-gear-dog-box-kit-racing-gearbox
    Gemini: Apparently they'll be coming out with a limited run of the grA dog kits, which are stronger than before.
    APTuning: https://www.aptuning.com/store/audi...02j-race-gearset-1st-4th-fits-5spd-fwd-detail
    Quaife: https://shop.quaife.co.uk/quaife-vag-6-speed-synchromesh-gearkit

    2. Lower pinion girdle: This is a typical weak spot on these boxes and helps to brace it.
    APTuning: https://www.aptuning.com/store/vw-c...9/aptuning-lower-pinion-bearing-girdle-detail
    There are other companies that offer these.. APT is the only one I'm aware of the machines the box to fit snug, which adds extra support.

    3. ARP bolt kit:
    http://arp-bolts.com/kits/Make.php?_Make=28&_EngModelID=*

    4. Billet steel shift selector
    Gruvenparts: http://www.gruvenparts.com/02a-cable-transmission-short-shift-kit/
    Again, others make this, but Gruvenparts is the best quality I'm aware of.

    5. Release lever
    APTuning: https://www.aptuning.com/store/vw-c...ace-stage-2-02a-j-clutch-release-lever-detail

    6. Differential flanges:
    APTuning: https://www.aptuning.com/store/vw-c...ng-02a-heavy-duty-differential-flanges-detail


    That's all I have.. was looking into upgraded shift forks as well, but haven't been able to find any.

    Also, I heard of people splitting open their angle drive casings.. but assume these are extreme conditions. Someone in the states was apparently making a billet angle drive but I can't find any info on it. I've been trying to track down as much info and history as I can regarding my gearbox. It's a 1-6 speed Gemini kit in an 02C. The guy I bought it from in the UK bought it from a proper VW Motorsport nut in Holland. The end casing is stamped w/ "T. Vos". It's rumored to have been an actual VWM works gearbox in it's day for a Rallye Golf, but I haven't managed to confirm yet. One interesting note though, it has an aluminum angle drive casing. All the Rallye Golf's came with steel angle drives while the Passat syncros (and maybe country golfs and gold syncros?) came with aluminum ones. When I noted this I was disappointed because it didn't match with the story. Then, while talking to the Gemini Transmission guys, I learned that VWMS had made a special aluminum angle drive casing for their works cars, which Gemini knew about because they made the gear kits inside.. I don't know how I can confirm this aside from taking it apart, which I plan to do at some point, but would love to hear more info if anyone has any!

    Obviously the way you drive, the oil you use, and proper maintenance go a very long way too.

    Would love to hear what else others have done to make their gearboxes of this generation last longer.

    Cheers,
    Isaac
     
  2. HPR

    HPR Administrator Admin

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    Other companies that do 02A / 02J gearkits.... MTS-Motorsport, Samsonas, Bacci, Drenth, SP2000...


    The new Gemini grA gearkits are pretty much the same as before, but have now different shift gears and dogrings ( now with 6 dogs against 8 before )

    On the output flanges these are often supplied by the Diff manufacturer and have often a different diameter /spline on the shaft
     
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  3. Isaac Pettit

    Isaac Pettit Paid Member Paid Member

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    Thanks for the comments. Yes, thats what GT told me also.

    HPR with all your knowledge and history in the Motorsports realm there, did you ever come across a T. Vos? The director at Gemini apparently said it rung a bell but couldnt remember any particulars.. I know its a long shot.
     
  4. HPR

    HPR Administrator Admin

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    T. Vos ? Not a name that rings a bell to me..
     
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  5. Isaac Pettit

    Isaac Pettit Paid Member Paid Member

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    Thanks for the potential lead Hugo! I've sent a note as suggested.

    Cheers,
    Isaac
     
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  6. Hotgolf

    Hotgolf Paid Member Paid Member

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    From what I've seen over the last 15 years you won't need the drive flanges, you can mod a std lever to be heavy duty, and you can make your own number 4. You can get PB shift fork bushes and pins from MTS (I also make them when I'm doing motorsport boxes).

    Gearsets you've listed are all much of a muchness. another is Doc Octane although his idea on preloading is well fxxked up and whacky!

    The name on the end will be the builder, who maybe hard to track down.
     
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  7. Isaac Pettit

    Isaac Pettit Paid Member Paid Member

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    Thanks for the added info Martin, seems appropriate that you'd chime in since based on reading old threads you've built more than a few gearboxes for other members on here!

    Is there a general rule of thumb for size of shift fork bushings (20 or 21mm) and shift rod support (15 or 16mm) for the Gemini 02A boxes, or just measure and see what you have?

    Seems MTS only have the 15mm bushings.
     

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