Testarossa dreaded differential issues and questions

Your friend made a diff in Spain? Is this a new source for the diffs? That would be great to have more options...

Also, with the side cover off... anyway to see the diff with a fiberoptic camera?

Bo

 

Sorry my English is bad.... My friend has a firm to repair automatic and manual tranmission and is the Oficial representative for ZF transmissions in Spain Técnicas en Transmisiones Automáticas - T.T.A. S.L.. He has bears in his eyes and is no typical spain... he works perfect an has many cars, also 512TR and F40. He is at the spain Ferrari club and can repair the diff without new parts. The problem is to get a new main shaft, but the problem ist, that it is not easy to repair the 512tr transmission. The firm which know how to make, do not want to explain how it goes. They want to make this job to earn money. I do not trust Ferrari specialist, because many of them are not good working, but they make many bla bla bla...that only they know how it goes....The knowledge they want to hold by them! Some people are here also so thinking!

 

for the main shaft I payed 3636€ from Tandler in Bremen

 

Maybe someone can correct me but isn't the "main shaft" supposed to break in order to protect the diff similar to a fuse? So making it stronger only transfers more stress onto the more critical and expensive components.

 

nearly the same I payed and just let do 2 shafts for my competition.
one is inside and the other I just prepare a second gearbox

next what would break is the shaft from the primary gearbox to the main gearbox. you may use/need this shaft from rob hayden from australia. the stronger shaft in my competiton never has been broken koenig told me, but mine has been broken. rob´s shaft still is ok

 

No, the main shaft is a gearbox part. The part you're thinking of is called the quill shaft. It is the fuse in the drive train. It connects the drop gears to the gearbox.

 

Wow, that broken mainshaft is amazing. The part that broke is simply the splines that slide inside the quill shaft. So, the quill shaft didn't do it's job. Did someone upgrade the quill shaft in that car to a stronger one? This is exactly why I don't do it. The quill shaft is easy to replace. The mainshaft is not!

 

not really right scott. I had a broken quill shaft that was borken not at the rear, it was broken near the mainshaft and so I had a lot of work to do.

but also had a broken mainshaft with the original quill shaft

I have inside meanwhile the quill shaft from rob and the mainshaft made in germany and until now no more problems

 

Tim, take my advice: find bb-Motors in Stuhr / Bremen. (0170-2951513) Owners is one of very few super gearbox makers in EU imo.

I took my gearrbox (gb) from Holland to him ... fitted the Forza Components diff and a new produced crown and pinion for me ...

Good Luck and tell us HOW all was repaired please (+ fotos) !

 

I wonder if you have read ALL in my thread ... and if so I wish you luck !

 

at the moment we built special tools to get out the shaft upstairs.... I am happy that my Maranello is running...and racing and I still dream that my F512GTB drives also on Nordschleife one day..
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Very thorough analysis. Thank you for taking the time!

Just curious how many known failures are there? Was that shown in graphs? What percentage based on all the cars that use this welded carrier?
(Not concerned w miles/years/maintenance/how driven etc. All that gets lumped together as variables.)

 

The quills shafts job is to transmit all the power and not be a "fuse" in the system. However, I agree it is far better for this part to break instead of the more expensive gearbox shafts.

We have an upgraded shaft that is both stronger and at the same time more flexible so that it minimises the shock loadings on the main gearbox shaft.
The result is a stronger and more reliable drive train all together.

Phil

 

From the feedback I received and with noted assumptions, the total failures came to 150. This was shown graphically and also mentioned in the legend under "N". Here it is again.

In this regard, there are approximately 2.1% failures to date. It was also mentioned that the Boxers and early 512TR's also contained the welded diff which added approximately another 4000 vehicles but did not add to additional failures. In this case, the failure total is 1.4%.

So the analysis was conducted as worst case i.e. 150 failures over 7000 vehicles if we don't consider diffs replaced by Ferrari which will be difficult to assess.
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Thank you!
So 2%------- Now I know my tolerance. Based on what I read from various sources, I couldn't stand the odds and replaced the carrier.

Also - another poster mentioned using a scope. I had a scope and couldn't see anything well enough to conclude anything. Then I did the logical approach, and bought a much better scope And big surprise, pretty much same result. Nice clean thick gear oil coating those parts and that weld were absolutely inconclusive to me. I could have argued either way based on that examination, but know I would have been lying to myself. This further convinced me I was never going to be happy and accepting to continue with this part. I got so nervous, I was uptight that I gave a friend a ride in the car before changing it 'cause all I could think of was, I've got the new part on the bench, and watch it break now!

 

^^
Right on but notice from the histogram that ~2% is today and there's still a large proportion of vehicles that have not yet made it to the reported "critical" mileage point.....if mileage is any factor/variable related to failure. This is why the survivability plot predicts 2.6% failures at 40,000 miles

 

More interesting! Well the psychological stress was no thrill-ride. I heard about this 15 yrs ago, and shrugged it off. 10 yrs ago there was a murmur about this which started to get higher priority until about 6mo's ago, I just had to replace it.

Of course Murphy's law probably means since I changed it, the carrier would have never broken That's ok, Still glad to have a billet part in there.

 

Built to press the shaft out....and now it works...
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Thanx for very nice write-up/report.

I am happy I am not in your shoes .... GOOD LUCK !

 

I have a video from the work, but cannot load it here...

 

Make a YT first Tim !

 

Done...
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New part looks superb !

All fitted yet Tim ?