365bb transaxle rebuild, interesting find | FerrariChat

365bb transaxle rebuild, interesting find

Discussion in 'Boxers/TR/M' started by Nate365, May 19, 2015.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. Nate365

    Nate365 Rookie

    Oct 9, 2005
    24
    Northern VA
    Full Name:
    Nate Stevens
    #1 Nate365, May 19, 2015
    Last edited by a moderator: Sep 7, 2017
    I have been working slowly through my '75 BB in an effort to get it roadworthy after many years of under use. I have been focusing on the major mechanical assemblies - suspension, steering, uprights, engine & transaxle, all of which have required MUCH cleaning get years of baked on crud off, and allow a decent assessment of needs. The heads are not pulled yet (debating on pros and cons still) but most everything else is broken down without too many strange things noted so far.

    Two exceptions in the transaxle area that I thought might be of interest (haven't noticed similar things in previous BB threads). My original plan was to install a Newman diff bought several years back, and to check syncros etc as I'm not sure when they were checked last. After disassembly and cleaning, the main issue found was not a bad factory differential, but the obvious weak spot visible inside the quill shaft bore of the large differential side housing. Due to the milling for the bearing on the far side, the material here is VERY thin. I didn't see anything strange at first, but when the light is right, it became clear that the machined areas actually 'intersect' at one point, creating a small break-thru about the diameter of a pencil lead. Then, the area of weakness along the base of the bearing bore (illustrated in the last pic) extends maybe 20 cm from there.

    In looking at the part one could easily argue this super-thin area isn't structurally important, but it's not what I hoped to find in there, nonetheless! Anybody seem the same or similar thing on another 365 (I assume this was fixed for later BBs)?

    Fwiw, all in all, the OEM differential looked ok - no visible cracks on the weld, at least. Regardless, I'll be glad to see it go, one less thing to worry about.

    The OTHER find was a 'lozenge' shaped piece (looks like a bearing roller or a small detent pin), laying in one of the two forward gearbox compartments, which does not match the size or shape of anything else in there (e.g., it's shorter than the various rollers in the gear train - - will post a pic shortly). Appreciate any thoughts, Nate
    Image Unavailable, Please Login
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #2 Steve Magnusson, May 19, 2015
    Last edited: May 19, 2015
    How about item #6 or #7 here:

    Ferrari 365 GT4 BB Parts : Table 23 - GEARBOX CONTROLS (UP TO CAR NO. 17535)

    parts of the shift rod lockout system? Page E33 in the TR WSM has a good cross-section drawing showing these parts that match your "lozenge" shape description well (and I'd have to guess that they used this approach on all the flat 12s -- i.e., something carried over from BB to TR, not something invented new for TR).
     
  3. Nate365

    Nate365 Rookie

    Oct 9, 2005
    24
    Northern VA
    Full Name:
    Nate Stevens
    Thanks Steve, that has got to be it. I'll double check all the parts associated with the forks, thought everything was accounted for but must be one lozenge short.
     

Share This Page