Auto Box Speedo Drive | FerrariChat

Auto Box Speedo Drive

Discussion in '365 GT4 2+2/400/412' started by wda24729, Oct 19, 2020.

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  1. wda24729

    wda24729 Formula 3

    Sep 22, 2014
    1,000
    Devon, UK
    Full Name:
    Graham
    #1 wda24729, Oct 19, 2020
    Hi Chaps. Is there anything special about the Ferrari angled speedo drive that warrants a price exceeding £1000? At the end of the day, its a 3 speed GM box used by many different manufacturers but maybe the connection to the speedo cable on ours is a different fitting or the drive ratios different?

    Mine has a very slight weep on it and although Ive been told they quite often leak, it does annoy me and was wondering if it was worth taking a punt on something like this?

    https://www.sngbarratt.com/English/#/UK/parts/54a3ca32-a590-4603-ae93-0733d479d66c?gt=Speedometer%20Cable%20Angle%20Drive%20for%20Jaguar%20Daimler%20Hearse
     
  2. raemin

    raemin Formula 3

    Jan 16, 2007
    1,858
    Lyon (FR)
    Full Name:
    R. Emin
    #2 raemin, Oct 19, 2020
  3. wda24729

    wda24729 Formula 3

    Sep 22, 2014
    1,000
    Devon, UK
    Full Name:
    Graham
    #3 wda24729, Oct 19, 2020
    That's one of the ones I was looking it. When you say damaged, mine is just a slight weep from the threads but I can't get it to seal quite right despite how many different washers I try.
     
  4. It's Ross

    It's Ross Formula 3

    Jul 30, 2007
    2,028
    Barrington, Ill. USA
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    Ross
    #4 It's Ross, Oct 19, 2020
    There shouldn't be any oil there to begin with. The GM part with the driven gear has an oil seal for the plastic gear, I suspect that is your culprit as its a common leak point.
     
  5. wda24729

    wda24729 Formula 3

    Sep 22, 2014
    1,000
    Devon, UK
    Full Name:
    Graham
    #5 wda24729, Oct 19, 2020
    Well that's frustrating as the box was refurbed not so long ago. Thanks Ross, this could be a cheap fix then, except I know I have to disconnect the prop in order to lower the box enough to get the angle drive out....grrr!
     
  6. Part Time

    Part Time Formula Junior
    Silver Subscribed

    Dec 16, 2013
    494
    Port St. Lucie, Fl
    Full Name:
    Gary Shore
    #6 Part Time, Oct 25, 2020
    I resealed many of these as a GM tech from the 70's to 80's, two seals, one large black o-ring to seal alum housing to trans case, a small lip type seal against the shaft with or without a spring/wire retainer to hold it in place. Also check the plastic shaft where it goes thru the lip seal for a worn-in groove.

    The numbers cast into the outside are the number of driven teeth gear that particular housing will accept, because as the teeth/diameter increases, the housing center hole "travels" away from true center to make room for the larger gear.

    The angled drive units are mostly on Covettes and other tight space sports cars using the TH400, never needed on pickups or SUV's.
    I "used" to have 2 or 3 of these on my work bench back in the day.

    Gary
     
  7. wda24729

    wda24729 Formula 3

    Sep 22, 2014
    1,000
    Devon, UK
    Full Name:
    Graham
    #7 wda24729, Oct 26, 2020
    In true Ferrari or maybe 400 fashion, this was a little trickier than normal. The only shaft seal is buried deep within the aluminium housing which you have to drift out. The new one (very tiny) is the type with a steel surround which you have to press back in place. No plastic items on this one!

    Anyway, all done and no more leaky trans :).

    And for info, you don't need to disconnect the prop as when you loosen the aluminium housing, there is enough room to tip it downwards with the angled drive still attached. Only discovered this after disconnecting prop so I could remove the angled drive first :(

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