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Testarossa gearbox rebuild

Discussion in 'Boxers/TR/M' started by Paul Colville-Nash, Aug 16, 2018.

  1. Paul Colville-Nash

    May 18, 2018
    16
    London
    Full Name:
    Paul Colville-Nash
    So, yet another blown diff has surfaced from what started life as a drive shaft oil leak, with the heart-sinking sound of tinkling metal when the diff carrier castings loosened. Amazing the car was still driving! Pictures of key components below!!
    Anyway, many thanks to many on the site who responded to my initial questions and apologies to Scott for unintentionally hijacking his threads - the resurrection took on a life of its own which I hope is a testament to his originals! Forza Ferrarichat ❤️
    Anyone where I was a few weeks ago start here!
    https://www.ferrarichat.com/forum/threads/installing-my-new-diff.409047/
    https://www.ferrarichat.com/forum/threads/cleaning-up-my-diff-install.504212/
    So, not going to repeat all of that content, it speaks for itself, but hope can add to this resource as these have been great helps alongside the Ferrari WSM which is not the easiest thing to follow, let alone when it is missing key info and assumes so much.
    So, can we add other related links and content to this thread please to get everything we can indexed together in one place - spares, hints and tips, missing info etc; what I learn (mainly from all of you!) I’ll add here. Important to me we acknowledge the generosity of those giving up so much of their hard earned knowledge - for me so far biggest thanks to “quazipsycho” aka Scott (as above) and “Turbo-Joe” aka Romano, but also everyone who has and will chip in.
    Also, although I appreciate not all experiences are the same, thanks to my local Ferrari dealership in Lyndhurst whose service manager and their gearbox tech have been happy to inspect bits and offer opinions for free to help me (they’ve even lent me special tools in the past so I can diy) and also Maranello Classic Parts in Egham who have also helped a lot and hunted out missing information and helped sort the parts jigsaw as what should be in the gearbox by its number wasn’t!

    As well as pictures below, magnetic plugs like Christmas trees, swarf throughout and oil like mercury! Future posts hopefully shorter!

    Left Hand diff carrier casting
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    Anyone need a second hand diff carrier bearing?

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    Diff casing -contents scrap too! The shim in the top of the blown casing is actually that for the LHS diff carrier bearing.
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    Crown wheel survived pretty much ok, few marks, biggest below presumably where it ate some bearing cage, but not on drive/coast contact areas and both this and the pinion (latter unmarked - phew!) passed crack testing
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    Attached Files:

  2. ago car nut

    ago car nut F1 Rookie
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    Aug 29, 2008
    4,219
    Madison Ohio
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    David A.
    I posted my gearbox rebuild here last year. Look under posts by "ago car nut".
     
  3. turbo-joe

    turbo-joe F1 Veteran
    Silver Subscribed

    Apr 6, 2008
    5,372
    southwest germany
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    romano schwabel
    sad to read that again a diff is broken.
    so again to all that don´t believe: it is only a question of when the diff will break, not if.

    but really nice to read that the official F dealer gives you the special tools to do it yourself. I was buying some tools or made by myself.

    so you will do also the complete gearbox by yourself?
     
  4. qwazipsycho

    qwazipsycho Formula 3

    Oct 30, 2004
    1,108
    Utah
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    Scott
    My mouth still hangs open when I hear people say this problem is caused by abuse. This is a Ferrari factory defect. No doubt about it. You could have taken those pics from my car. Identical damage except I didn't gouge my crown gear.
     
  5. Ludwig

    Ludwig Formula Junior
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    Mar 27, 2006
    265
    Redmond WA
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    Ludwig Allegra
    Makes me feel better about replacing mine in the boxer. Really fortunate about the crown gear! seems that this will be no issue.
     
  6. Paul Colville-Nash

    May 18, 2018
    16
    London
    Full Name:
    Paul Colville-Nash
    Yes - they weren’t comfortable doing it as after market parts etc and the tech and service manager was honest enough to say they had never done one and knowing me thought I could do this with their help and save a huge bill! They know they get the service work as around me they aren’t that different from the specialists - definitely more but not by enough! And I have a great relationship to go with. TBH they said haven’t the tools for this job either so like you I have made my own but they said they could source further help from Ferrari and other restorer contacts they have if needed. Can’t ask for more!
     
  7. Paul Colville-Nash

    May 18, 2018
    16
    London
    Full Name:
    Paul Colville-Nash
    Yes really lucky - I’ve seen some posts where they have been completely destroyed. Luck of the gods! I have driven her hard but fair in my view so “when” is right if you do. I ain’t Miss Daisy - it’s all about fast but smooth progress - even my driving instructor all those years ago was “there’s a speed limit so why aren’t you on it?”! And I threw a lot more at my 911 and RS6 (many more miles, track days etc) which both just shrugged it all off and never missed a beat. We all know the underdesign flaws here and what will expose them - don’t kid yourself unless yours stays jacked and just gets polished But what a waste if you do...
     
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  8. Paul Colville-Nash

    May 18, 2018
    16
    London
    Full Name:
    Paul Colville-Nash
    So, thanks to Turbo-Joe’s warning to strip and clean out the synchro’s. Having put them through a parts wash as complete units, 1st/reverse and 2nd/3rd pretty clean when dismantled but the inserts in the 4th/5th synchro packed full of a waxy mess of oil and swarf which took a pick to get it out and which couldn’t otherwise be easily seen. Don’t skimp on your prep.
    Synchro wear and play all good - all well over a 1mm. My TR90 workshop manual identified the measurements to take but not the values but thanks to Maranello now have these from same rings in the 365BB - scan below.
    Blued the synchro cones on the gears - nice even patterns on engagement and grip strongly.

    TR90 Manual
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    365BB info in scanned pdf

    Blued 3rd gear synchro ring/cone engagement example
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    But 2nd gear shot and had to replace...seems this type of damage not uncommon (look bottom left of gear teeth). Rest of gears all good. Not sure if this is wear through poor case hardening or in fact ‘abuse’ from any locking up of the crown wheel when the diff blew. Could be cracked but clearly not worth bothering with... Interesting this gear part number shouldn’t have been in this gearbox according to the number on the casing. Makes you wonder what the past was before I bought her in 2000 (main dealer history, no gearbox work recorded. But then could just be Ferrari business as usual...
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    Few more bearings to get then the reassemble!
     

    Attached Files:

  9. Paul Colville-Nash

    May 18, 2018
    16
    London
    Full Name:
    Paul Colville-Nash
    Random insights etc...

    As above see ago car nut’s rebuild post here - lots of useful hints and pictures of tools etc
    https://www.ferrarichat.com/forum/threads/tr-transaxle-rebuild.564813/

    Shaft ring nuts
    One the ring nuts are opened up where they are locked to the shaft keyways, a compressed air-driven ratchet gun makes light work as the mass of gears on the shaft has sufficient inertia to not move when cracking the torque applied. Watch out for reverse thread ring nuts (etc) though as it’s not a very forgiving tool if you go the wrong way!

    Removing the main shaft
    This had me a little stumped as should come out the front it seems, but clear wouldn’t as gears in way. So, after a head scratching, tapped it backwards into the diff housing (reverse idler drops as Turbo-Joe noted in Quazipsycho’s original post linked above) until I could unload all the components on the shaft in front of the centre bearing. Then tapped out front bearing shell and withdrew the shaft out the front of the casing. Easy!

    And on the subject of bearings:
    Ferrari #103031 centre lay shaft Timken 28158/28300
    Ferrari #101635 pinion end bearing Timken M802048/M802011
    Ferrari #101634 left hand diff carrier bearing Timken 368A/362A
    Ferrari #125390 right hand diff carrier bearing Timken 28580/28521
    Readily available at a fraction of the Ferrari price though if you want country specific can get harder and might cost a little bit more to get suppliers to check. Mine were all English or US Timken.
    All the shells/bearing carriers in the gear casing come out very easily when lined up properly but if only slightly out of line will lock solid. Take your time and don’t force them.

    Everyone, please keep chipping in.
     
  10. ago car nut

    ago car nut F1 Rookie
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    Aug 29, 2008
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    David A.
    My second gear looked like that also. 1st gear was much worse. Replaced both sets, replacement gears from Modena Australia, had less helix and looked like a better gear profile!
     
  11. MOSS

    MOSS Formula 3
    Rossa Subscribed Owner

    Apr 28, 2004
    1,004
    I had a twin turbo 700hp TR with stock differential and never had an issue so I disagree with it being a factory defect. I have owned 4 TR cars and
    never an issue. Its not a Ford 9 inch rear end so you just have to understand its a road car not a jackrabbit start car or drag car.
     
  12. Paul Colville-Nash

    May 18, 2018
    16
    London
    Full Name:
    Paul Colville-Nash
    I definitely never used mine as either of these, though what the previous owner did is always an unknown :(. There’s more than enough posts/experience, even if not all are posted here, to say this is an issue without any recent history of abuse from current owners and that it can happen even if current owner drives sympathetically. But equally a lot of people saying driven many happy miles without this issue.
    Given this is a weld failure rather than a mechanical fixing failure, perhaps this is simply a quality control issue on the welding? - compared to number of cars made, it’s not even close to a majority failure rate (yet). Welding is to me is always a less predictable method of fixing, very dependent on the operator being meticulous and who knows if they ultrasound tested the welds after, etc etc.
    So, if you have a poor weld out of the factory (look at those recent French nuclear reactors failing their weld tests!) to start with, I think “when” is right. Unfortunately, until it fails, it is not easy to check what you’ve got:confused:! Pays your money, take your pick...
     
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  13. xplodee

    xplodee Formula Junior

    Jan 3, 2017
    716
    Allentown, PA
    Full Name:
    Tim
    More info/pics of TT TR please please please :)
     
  14. ago car nut

    ago car nut F1 Rookie
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    Aug 29, 2008
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    David A.
    1st gear wear and spalling is not uncommon on a TR.
     
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