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Differential Seal Question

Discussion in '308/328' started by skipgt4, Aug 9, 2021.

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  1. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    #1 skipgt4, Aug 9, 2021
    i have a 1978 308 GTS i had to do the CV Joints and while i was in there i was going to do the differential seals. i started on the LH side, pulled the seals out and cleaned things up some. i was going to push the new seal back in but I don't see the shoulder or stop that the seal should seat against. Am I looking at this wrong or is it really not there?
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,806
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, Aug 9, 2021
    Last edited: Aug 9, 2021
    The tea leaves in the SPCs indicate that what you have is correct for a 1978 (no shoulder for the seal -- just drive the outer face of the seal to be flush with the surrounding area). The online 1976 308GT4 SPC shows that piece as 104294 becomes 106806 becomes 108226, and the main illustration shows a shoulder for the seal (and I assume the main illustration is of 104294) -- whereas, the sub-illustration shows the updated part with no shoulder for the seal. The 1978 308B/S SPC shows that piece as only 108226 and the illustration (based on 108226) shows no shoulder for the seal:

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    waymar and lm2504me like this.
  3. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    #3 skipgt4, Aug 9, 2021
    thank you. good to know im not crazy. from everything i read here I thought there was going to be a shoulder on this side.
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,806
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #4 Steve Magnusson, Aug 9, 2021
    It is one of the problems we have that Ferrari never did a complete 308B/S WSM to update the changes that got implemented along the way. The copy of the 308GT4 WSM that most of us have was written circa 1975.
     
  5. Glenn308QVturbo

    Glenn308QVturbo Rookie

    Sep 20, 2017
    34
    Full Name:
    Glenn Orell
    #5 Glenn308QVturbo, Aug 13, 2021
  6. smg2

    smg2 F1 World Champ
    Sponsor

    Apr 1, 2004
    16,333
    Dumpster Fire #31
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    SMG
    #6 smg2, Aug 13, 2021
    I've torn into all the gearbox variants from early 74gt4 to 89 328 and mondials... None have had a shoulder stop for the seal. Early gt4 was a steel though.
     
  7. skipgt4

    skipgt4 Formula Junior

    Nov 3, 2003
    446
    GR Michigan
    Full Name:
    Charles VDB
    #7 skipgt4, Aug 17, 2021
    Mine did look like the photo posted by Glenn above but the picture in the tutorial by Birdman sure looks like it has a shoulder.
     
  8. waymar

    waymar Formula 3

    Sep 2, 2008
    1,354
    Northeast, PA - USA
    Full Name:
    Wayne Martin
    #8 waymar, Aug 17, 2021
    The carrier plate in the BM tutorial shows no lip. The picture of the opening w/o the seal clearly shows the spacer shim for the big bearing pre load. Having disassembled the differential it becomes more obvious.
     

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