348 Gear oil

Discussion in 'Technical Q&A' started by Ksullender, Mar 29, 2005.

  1. Ksullender

    Ksullender Formula Junior

    Sep 3, 2003
    I have searched the threads, but wanted to see what the most recommended gear oil is for a 348? - Thanks
  2. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Rossa Subscribed Owner

    May 4, 2001
    Birmingham, AL
    Full Name:
    I think there has been general agreement for Redline 75/90 NS with a splash of NS additive as needed, at least for the 308's here.
  3. spider348

    spider348 Formula 3
    Silver Subscribed

    Nov 3, 2003
    Full Name:
    Hello, I currently use Redline 75~90 NS GL5 gear oil. I also add Redline friction modifier at approximately 50% of the Redline ratio used in their standard 75~90 gear oil. Improved shift function with minimal differential chatter. Works in my 348 spider.
  4. dapper

    dapper Formula Junior

    Nov 10, 2003
    Bristol, UK
    Full Name:
    Another recommendation that occassionally pops up is Castrol syntrax 75-90, not sure how available that is though.
  5. zan

    zan Formula Junior

    Nov 15, 2002
    Full Name:
    Mark M
    I'm also deciding which oil to run in my diablos trans & diffs.
    Read this about GL5 oils, from the Redline website:

    GL-5 gears oils which are required in hypoid differentials
    are not used in most synchromesh transmissions
    because the chemicals used to provide the extreme
    pressure protection can be corrosive to synchronizers,
    which are commonly made of brass or bronze. Typically,
    the use of a GL-5 lubricant in a synchromesh
    transmission will shorten the synchronizer life by one
  6. spider348

    spider348 Formula 3
    Silver Subscribed

    Nov 3, 2003
    Full Name:
    This issue has been discussed before. My understanding is very early transmissions/ transaxles used softer materials for the synchro assembly. My underdstanding is Ferrari does not use brass or bronze. Rebuilt my 348 gearbox. Synchros were not brass or bronze. Note, the paper details all GL-5 type gear oil, not just the Redline product. My Ferrari specs GL-5 gear oil. Just my opinion, John.

    From the Redline site:
    75W90 NS

    This GL-5-type geal oil doesn't contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting. Can also be used in racing limited-slip differentials where weak spring design causes too much wheel spin.
  7. kenyon

    kenyon F1 Rookie

    Oct 7, 2002
    East Yorkshire
    Full Name:
    Justin Kenyon
    This is what I use and my box is slick at cold start ups. I will never use anything else.
  8. ernie

    ernie Two Time F1 World Champ
    Owner Lifetime Rossa

    Nov 19, 2001
    The Brickyard
    Full Name:
    The Bad Guy
    I'm running Mobile 1, 75-90 in mine.

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