Diff project

Manufacturing failure, yes even Ferrari makes them and these have nothing to do with how car is used. I suspect all these diff's will fail, chainge them out!

 

as mel always said ( when he still had his TR ):
it is not a question if the diff will break - only when

 

Haha, I certainly can prove to the contrary but if that is the propaganda that you want everyone to believe then you have every
right to voice your opinion and you are a smart guy for sure. No need to scare future Ferrari TR owners in my opinion. If you want to replace it on your first engine
out and have the money then go for it. It certainly gets you extra insurance and peace of mind. If I do another TT car I will do it.
As for the 4 I have owned over the past 25 years, one being a twin turbo and zero differential problems...well, speaks for itself : )
Its not luck and I certainly did not accidentally get a "better" one at the factory.

 

I was told about one car in Norway that have had three broken diff's, you know; official service can only replace genuine parts and third one was bad.

 

Amazing the negligence that these cars receive. Money does not buy common sense or a mechanical aptitude. That's for sure.

 

I asked not one, not two, but three factory trained mechanics—all of whom were trained when TRs were still new at the dealerships, and who have probably 100 years of combined experience working on them. All three said the same thing, which was effectively, “not a big deal, don’t worry about it.” Of course, all three could have profited handsomely by making it a big deal, so...
YMMV

 

MOSS
you are sure not one of your diffs have been broken without your notice?
remember shamile´s car. after he sold it to the new owner there was oil leaking from the left diff cover. and the new owner was not driving much until leaking.
I think the diff problem is like las vegas: you can win and you can loose.
I myself like to be on the safe way with only changing the diff before more will break

 

Maybe a dumb question - is the 512TR differential the same as a Testarossa differential? I don’t read about as many 512TR failures.

I have shop manuals for both cars and the 512TR manual has a somewhat better (but slightly different) explanation of the preload process.

 

just now you only get from ferrari the diff no. 155099 for all TR, the 512 TR and the 512 M
have a look at eurospares co uk and you will see this. but for the 512 TR there was in once the no.146769
the 155099 seems to be original in the 512 M? but not have been in the TR 85 and 90
all diffs are matching to all TR´s and also all 512 BB and 512 BBi and also the 365 GT4 BB
but there are a lot of aftermarket manufacturers, much cheaper than the original

 

I believe the 512M was upgraded.

 

I know where 3 of the 4 are and the twin turbo. All good with no problems. Guys this amount of reported breakage is unheard of. 20 years ago you never heard of one breaking. My concern is more money in the economy and non car guys buying these cars to hotdog around and say "they own a Ferrari" but do not understand what they have. Its abuse that is killing these cars 90 percent of the time, not a flaw in the differential.

 

Again, let me say that an exotic car typically has a light duty differential unlike a 9 inch Ford. Shocking it with rough synchronized rev shifting , burn outs, jack rabbit take offs will tear them up. The answer is take it easy. Spirited driving is fine but stay away from shocking it. If you ignore all of this then buy yourself a handful of beefed up parts and let it rip!

 

Only 94TR is upgraded and the M


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Thanks, I am curious why it seems that 512TRs seem to suffer fewer failures, even with more power. Either the factory learned to weld better after 1991, the cars are newer, or, as they are generally more expensive, they are bought and used by different people.

 

Different diff.

 

I'd agree that my unscientific data collection here is that TR seem to crack the weld and then break the side cover out, while 512TR still sometimes crack the weld, but don't break the side cover as often. Wonder if they made some design changes to better prevent the two pieces (if cracked) from rotating relative to each other when cracked -- does anyone have a picture of the two cracked pieces from an early TR?

 

I knew the 94 had ABS which is cool and other upgrades but did not know they got the M differential. These units also got better, stronger propeller shafts.

 

512BB - Early Testarossa - 512TR

BB got better finish, weld is machined, but more later cars, less machining and worse job done.


I would think there as variasions with temperature treatment and that might make difference, between units, but more I would think age, usage and resonance, more kilometers would make bigger difference.

 

I changed my BBi diff carrier. When I learned about this problem, I didn't enjoy driving her. Every little noise made me fear the worst. There's enough common feedback to support the concern. True, I have no idea how she was driven regardless of the beautiful condition. Was it smooth? Who knows? This just compounded the anxiety. After changing, I just don't think about it and just love the music from that magnificent engine.

 

Just got the diff out of my '84 BBi. Visually it is OK, but I'm going to have it X-rayed and magnafluxed just to make sure there are no "cracks" or fatigue points. I'm going with; "If it ain't broke, don't fix it". Plus I can save some $.
Going to do the same with the transmission shaft.

I've never driven the car hard, except for some spirited highway use and some touring laps on the track, so hopefully everything will be OK.

 

on a BB or BBi I never had a broken diff - until now

 

Any details you can offer?

 

as I have written already: never had a broken diff on a BB or BBi.
only TR serie ( so tr, 512 TR and also one 512M )

 

Oh..OK. I misunderstood your post.
I thought it meant you'd never had a failure on a BB or BBi until now...and now you have..

 

That went lost from the German translation....bis jetzt....