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Gear change on 3.0 Sport

Discussion in 'Z3 Roadster & Coupé' started by lightning, Aug 7, 2014.

  1. lightning

    lightning Zorg Legend

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    Sometimes the gear change is notchy, and other times it is OK.
    It does not crunch, but kind of crashes into the next gear (mainly from first to second gear) maybe as if you did not press the clutch down enough?
    Other times it is fine.
    I have read that these gearboxes are notchy. But why is it sometimes OK? The car has done 54,000 miles. I removed the CDV and changed the clutch fluid. The pedal engages a third of the way up.
    I am wondering if the clutch could be
    faulty.
    But l had a Mazda MX5 that did this, and two new clutches failed to rectify it.
     
  2. t-tony

    t-tony Zorg Expert (I)
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    Have you changed the gear oil recently? At 54k it's hardly run in.:)
     
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  3. badman gee

    badman gee Guest

    I changed my gearbox oil at 48000 and it makes a big difference.

    It should hold 1.5 litres.

    When you drain it there might only be a litre or so in there.
     
  4. GazHyde

    GazHyde The Gaz Monkey
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    1st to 2nd on both the zeds I've owned have left a fair bit to be desired. Don't know how others find theirs.

    I get my gearbox & diff oil changed at every service now. Doesn't add much to the cost, and it made a big difference the first time I did it.

    Also added the Storm shorter heavier gear knob and that helps too.
     
  5. t-tony

    t-tony Zorg Expert (I)
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    Heavier knobs. . . . .. here we go again.=))
     
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  6. Mint

    Mint Zorg Expert (I)
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    mmm agree Tony, we haven't had a good knob thread for a few weeks;)
     
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  7. oldcarman

    oldcarman Zorg Guru (V)
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    And shorter also!!
     
  8. lightning

    lightning Zorg Legend

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    I changed the gearbox oil last month, after a lengthy gearbox oil discussion on the other Z3 forum.
    I ended up using Castrol 75w/90 which is their universal transmission fluid.
    After being told this was no good for the Z3 transmission, l contacted Castrol, who said it was OK.
    But they said l might be better with their 75w gearbox oil.
    However the 75w/90 is still in at the moment.
     
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  9. lightning

    lightning Zorg Legend

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    The thing l find odd, is that sometimes the gearchange is perfect (from first to second) and other times it is obstructive.
    It is totally random.
     
  10. GazHyde

    GazHyde The Gaz Monkey
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    Just checked my last service invoice and my indy used EP80 gearbox oil.

    Yes, mine is like that too. But as both of mine have been like it, I've just given it up as a "feature" rightly or wrongly.
     
  11. lightning

    lightning Zorg Legend

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    I don't want to start another "what gearbox oil" discussion!! As they go on and on lol

    When l get a chance l'll replace the oil with the Castrol 75w. But l don't think it will make any difference.
     
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  12. GazHyde

    GazHyde The Gaz Monkey
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    Wasn't trying to start a debate just found the receipt the other day when unpacking ;). A rare thing for me as I normally lose receipts like that... :oops:

    I didn't specify anything when I had it done, just asked them to change it. They could have put olive oil in it for all I know about automotive lubricants :bag:
     
  13. vintage42

    vintage42 Dedicated Member
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    Why do people use hard-shifting gear oil when BMW specifies ATF of much lower viscosity?
     
  14. lightning

    lightning Zorg Legend

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    BMW initially recommended ATF in the Z3 transmission, then changed the recommendation to gearbox oil SAE 75 or SAE 80
     
  15. vintage42

    vintage42 Dedicated Member
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    #15 vintage42, Aug 8, 2014
    Last edited: Aug 8, 2014
  16. lightning

    lightning Zorg Legend

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    I am not sure there would be any advantage in using 75w/80 over a straight 75 or 80w

    However, if that's what BMW are recommending, it will make people feel better if they use it.

    Castrol technical told me the higher weight is better for hot climates and l "might notice the gearchange is a bit sticky" if l used their Universal 75w/90 in the UK in winter. They recommended l change to a 75w.
     
  17. vintage42

    vintage42 Dedicated Member
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    BMW are not recommending 75W-80 gear oil. Castrol's is a synthetic API GL-5 with a viscosity at 100°C of 15.0:
    http://msdspds.castrol.com/bpglis/F...053593D/$File/Castrol_Syngear_75W_90_3750.pdf

    That is twice as viscous as what BMW recommends, and the sulphurous extreme pressure additives in GL-5 gear oil will shorten the life of yellow metal synchronizers.

    BMW recommend and sell a synthetic manual transmission fluid, Pentosin MTF 2, API GL-4 with no sulfur, with viscosity at 100°C of 7.7:
    http://www.pentosin.net/specsheets/Pentosin_MTF-2.pdf

    The proper viscosity should make shifts feel better.
     
  18. lightning

    lightning Zorg Legend

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    Castrol technical said that their "Universal" transmission oil has been specially formulated and has no additives such as sulfur that will damage gearbox internals.

    I specifically asked this question when l was on the phone to the guy.

    But I'll change over to the BMW stuff if l can get it for a reasonable price in the UK. The dealer wanted £80 for two litres, l'm not paying that
     
  19. t-tony

    t-tony Zorg Expert (I)
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    We recently changed the auto oil on a Z4 at work 7 ltr at £22.50 a ltr.plus lab. Glad I could do my own.;)
     
  20. lightning

    lightning Zorg Legend

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    When l bought the Z3 l thought, let's change the trans oil. So l went to the auto spares storeand bought two litres of gear oil "hey, it's a car gearbox, let's put gearbox oil in it"
    No, no, no l was told, your gearbox will fall to bits, your synchro hubs will become metal flakes attached to the magnetic drain plug, you will ruin the bearings, etc
    So l went back and exchanged the gear oil for the Castrol product, which Castrol themselves say is OK. I put it in the transmission and it did shift better.
    But no.....this is the wrong oil! It's too viscous, it's going to wear out my gearbox, changing will be "sticky"....what kind of alien transmission is installed under my gear stick, that cannot survive on automotive transmission oil, used in just about every other car on the road!! lol
     
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