Alpha Omega Racing Gearbox Rebuild

Discussion in 'Z32 Technical' started by Boll!, Mar 15, 2019.

  1. Martin Williams

    Martin Williams Active Member

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    In my opinion, your gearbox needs some serious work. If you have noisy 2nd/4th gears and you have metal in the oil you will never cure it by changing rubbers or oil. I suspect that you have lost case hardening from gear teeth or even have a broken or chipped teeth. If it were only the synchros cones that were damaged you would have brass coloured particles in the oil and it would be just more difficult to change gear. Get a new gearbox or get that one completely overhauled. Can you still get a Spec 2000 box because they were a great improvement on the original box.
     
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  2. bobbs

    bobbs Member

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    Its only just* been rebuilt
    Got the transmission back from the shop Sep 2016. Installed Dec 2017. Driven it around a little bit over the last year. Literally only done 2600kms. It still looks brand spankers.
    I seriously suspect the case hardening on the gears is wearing through, through pitting, galling etc. So I seriously need to source new gears. Only problem I can see from ordering from nissan is: I don't know what year model this transmission is, and useless nissan can't order parts without a Vin number (my vin is auto).
    Lastly, I don't want to get another second hand gearbox as this will be the 4th time changing the gearbox... Pain in the butt job for a skinny guy like me to do by myself.
    [​IMG]
     
  3. bobbs

    bobbs Member

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    Aaaand just realised they're out of business... Damn it...

    [​IMG]
     
  4. Boll!

    Boll! Active Member

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    I’m really not sure what they do to help with the 4th gears issue
     
  5. Fists

    Fists Well-Known Member

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    4th gear isn't a 'gear', it's a direct lock between the input and output shafts with the layshaft and gears totally unloaded so if it's noisy driving in fourth it's either bearing noise or the gears are rattling due to misalignment, worn teeth would be quietest in 4th. I can't think of any single reason 2 and 4 would be noisy (I assume the same sort of noise?) without affecting 1,3 and 5 so ZX299 is probably right about the dust boots lifting, I've had the same thing happen.

    RB25det gearboxes are functionally identical to ours but there might be small differences in alignment, shimming etc. that would trip you up trying to mix and match bits. Complete new gearboxes are available at around $3k, alpha omega or RGS among others should be able to organise you one if you can't deal with nissan. I think getting individual components out of nissan is dificult.
     
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  6. bobbs

    bobbs Member

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    Got the wifes car running so I should be able to start pulling apart the zed. It has rego in a couple of weeks so I might sort out a pink slip first.
    The amount of steel shavings that came out with the oil has me doubting rubber boots. Though its an easy check i can do on the weekend.
    If those after market gears are supposed to work, I'd like to try swapping them in myself. I originally bought tooling to rebuild it myself but ran out of time, space and confidence. I expected paying for a service (which I always try to do myself) would last more than a couple thousand Ks. Was definitely not worth the thousands I paid... As they say, if you want something done properly, you have to do it yourself. If they are indeed similar enough, shimming it properly would be a fun new skill to learn. Similar to shimming diffs with bearing blue etc?
     
  7. Shane001

    Shane001 Well-Known Member

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    Pulling the gearbox down is a big job, you'll need a decent press with wide enough engagement to press it apart and back together again. We started pulling my spare box down and it's been sitting partially disassembled now for about 2 1/2 years lol.
     
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  8. Martin Williams

    Martin Williams Active Member

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    As Shane said, its a big job. I watched Eric (A2Z) (God rest his soul) do one for me. You need the right equipment and know exactly what you are doing and what to look for. Yes its around $3K for a new gearbox, but its guaranteed to be perfect, it will have all the latest modifications and this will be the last time you have to change the gearbox. I bought one from the states a long time ago for US $1800 when A$ - US $ was 1:1. With air freight it cost me A$2200 and it arrived on my doorstep six days later. I believe they are still the same price in US just a crap exchange rate now. PS. Being skinny makes it easier to change a gearbox.
     
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  9. bobbs

    bobbs Member

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    yup, got a hydraulic press. Will probably need to drill a big hole through my work bench lol (I'll just use scrap wood from bunnings instead of ruining my bench)
    I also have an assortment of proper gear pullers from tiny to massive. Even comes with a mini hydraulic jack which is cute.
    I've stripped down the case and external parts off this box before with the intention of rebuilding it myself... But as I said, didn't have a clean space to work... or the confidence. Admittedly with the gear assembly out, it does look pretty daunting. I think I just need to grow some balls and just do it.
    I thought I had more photos uploaded online, but I cant for the life of me find them. I'll have to upload them from home, though its nothing special...
    [​IMG]
     
  10. bobbs

    bobbs Member

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    Being skinny definitely helps for reaching the top bell housing bolts. But lifting it up and aligning it is a challenge. Perhaps the correct adjective would be scrawny. Even with a transmission jack adaptor... I most certainly do not lift lol
     
  11. Shane001

    Shane001 Well-Known Member

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    Just be sure to remember the order everything came off in, and the direction ;)

    I found a 500mm extension bar with the universal joint made it much easier to get those top two bolts. SCA has em for about $20. Still need to drop the rear end of the gearbox down an inch or two for the passenger side.
     
  12. bobbs

    bobbs Member

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    I actually use all of my ratchet extensions and 2 uni-joints to get the top bolts. Quite unwieldy but I've done it enough times to get used to it.

    Yup, one of my biggest fears. Finally reassembling everything and all sealed up... then realise its all locked up because I installed some washer backwards or in the wrong order, too tight a clearance when bolted up or something like that. I'll just have to take my time and triple check everything. All part of the job I guess.

    I really would like to know more details about these though.
    So we've confirmed the FS5R30A OS Giken gearset will work with the Z32 TT housing?
    However I've found on one on sellers web page:
    Any idea what parts they're talking about?

    https://www.osgiken.co.jp/pro_gear/nissan.html
    So all up, I'm looking at:
    5 speed close gear set w/ input shaft: ¥325,000
    sandwich plate: ¥83,000

    Not sure what happened to 4th gear though... standard is 1:1 but this just says "-" Also I assume I can keep standard 5th gear and no need to fork out another ¥87,000 for their close ratio 5th gear. Or would it be incompatible thus making it a 4 speed... or only a 3 speed if "-" means "no gear"

    But yeah, pretty pricey indeed.
    [​IMG]
     
  13. Shane001

    Shane001 Well-Known Member

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    Yep, I used to have three extensions and a uni. For $20, the 500mm extension makes it 100% easier!
    Plus if you ever need to crack the chassis bolts for the FUCA's, the 500mm extension makes this so much easier also.
    Probably the best $20 I've ever spent on the zed lol!
     
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  14. bobbs

    bobbs Member

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    Wait... Never mind what I said about 4th gear... Just had a sudden shortage of brain cells... Derp. Now that I think about it... Now I'm not so sure what is actually making the gear noise in 4th. Maybe i've had some locator spring pop out somewhere causing some undriven parts to chatter... Hmm
    However if it is indeed just a rubber dust boot, i hereby give you all permission to smack the backside of my head...
    Maybe I'll make a video this weekend so you guys can hear it for yourself
     
  15. IB

    IB ?????

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    In the time it takes to make a video and upload it, you can check the boot is correctly fitted and have a celebration beer.
     
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  16. bobbs

    bobbs Member

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    Oh great... My shifter nob is royally stuck... Not even multigrips or vicegrips could make it budge. So i'll give it another crack tomorrow morning but I think i'll have to destroy the shifter in the process. Which is a shame as it was a brand new* leather oem one :( also I quit beer so all I get is a celebratory pat on the back. Fml right...
     
  17. IB

    IB ?????

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    You should be able to move the trim enough to check/fix the rubber boot without removing the knob. Turn the leather boot inside out as you lift the trim.
     

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