512TR Gearbox problem.

I am following this closely as I too will preventatively change my diff casing and possibly the quill shaft.

The '92 512 TR I just bought has just had an EO service, so not due for another 5 years.

My questions:
- would you wait for another 5 years to change the diff casing? (my car has done 47.000Km)
- can I have the diff casing changed without dropping the engine?
- if I change the diff casing only and keep the original quill shaft as a safety fuse, and the shaft breaks a bit later, can I change the quill shaft with the engine in place?

Context:
- If I have time, hopefully I may drive about 3000 Km per year.
- I drive carefully, always gently warming the car, never ever using full throttle in first and always double de-clutching to synchronize gears.
When the engine and gearbox are fully warm, I certainly do use full performance through the other gears, as the maker intended, though hardly ever over 6000 rpm as it is simply not necessary on this engine.

At the moment, when I use full engine torque, I have pictures in my mind of broken diff casings... I would feel better with a bulletproof gearbox (to go with the bulletproof engine!).

Thanks,

 

yes

yes, but a little difficult

this depends on where the shaft is broken:
in driving direction at the back: yes, without any problem
in driving direction at the front: no, because the rest will be on the mainshaft and this you can not get out without dismanteling the whole gearbox. but also may be then that the grooves are damaged at the main shaft

there is no bulletproof gearbox

as I mentioned in an other thread you may test by yourself if the diff-housing is broken or not. because of the diff-lock it is hardly possible when the car is on a hoist and the 1st gear is in to turn one rear wheel. so when you turn one rear wheel to the front the other will turn to the back. when you try to turn one wheel and this is really easy then you know that the diff-housing is broken and you have to change as soon as possible before more will get damaged. but as long as the diff lock is working fine you are on a safe side. because if the diff will break first it takes a while until more will get damaged. also when you see gearboxoil draining from the left diff cover and the seal is ok you know you have to change the diff

 

as I mentioned in an other thread you may test by yourself if the diff-housing is broken or not. because of the diff-lock it is hardly possible when the car is on a hoist and the 1st gear is in to turn one rear wheel. so when you turn one rear wheel to the front the other will turn to the back. when you try to turn one wheel and this is really easy then you know that the diff-housing is broken and you have to change as soon as possible before more will get damaged. but as long as the diff lock is working fine you are on a safe side. because if the diff will break first it takes a while until more will get damaged. also when you see gearboxoil draining from the left diff cover and the seal is ok you know you have to change the diff
Romano,
So I think what you are saying is, if the diff rotates to the rear real easy the diff case is starting to fail? Should a good diff rotate to rear any amount if not damaged?


Ago

 

no, then the diff housing already is broken, but all other still may be ok

yes, but very hard

 

So, keeping in line and in one thread, I will not be added to the list of new diffs in my 86TR.

About two years ago, I started to hear the odd thump out of first gear, on very low rpm. I didn't drive the car last year as I need up moving out of the city, and had a home to attend to, but I did drive the car a little in 2013. The thump would not happen often. Winter came early in Toronto, and summer never really arrived here this year.

I drove the car a total of 5 times this summer as now I was settled in our new home, and every time I drove it , even slightly, this thump continued. Since the weather never got better for 2014 , and I was on year 7 for my belts, I said **** it ...it's time.

In she went for the engine out, and the engine off the tranny .... The diff has two very light cracks around the weld .... And by light , I mean you need a shop light and look ..... But the two cracks are present. It will not be present on a picture, therefore no pictures.

Also to note, the car in 3rd gear had a slight shake this past year, the other gears do not , just third. On acceleration in 3rd it would be firm. On deceleration it was also fine, but cruising in 3rd, it had slight shaking. I am making note, as I would like to document this for other owners of my experience , if this is any clue to help and go in.

The other best part in all of this, today we found the clip on the oil/water pump chain in the pan, as my car never got the update ( another bullet I dodged I guess ). Will be replacing that as well, just waiting for my diff from phill this week. Will post pictures in the coming weeks as we progress. How many does that make now with new diffs in the Testarossa ?
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The thump in first could be loose ring nuts at the front of the main or counter shaft.
Take the front cover off and check them. Better still take them off and reinstall with high strength locktite.

And do not ever, ever let anyone use silicone sealant ever again between the motor and gearbox. Ferrari destroyed a lot of motors that way. Subject of another TSB. Don't you guys get mail up there?

 

He hasn't looked at the tranny yet, but will advise him.

The silicone is scraped off , we know about that, as I developed a light leak the last couple of years from there, another thing I wanted to address.

After 15 yrs of ownership, this is the first time I'm taking the engine off the tranny, I had no reason too before this.

 

I figured, but someone did. Use anaerobic 813 going back together.

 

Thank you Brian, will let you know once he looks at the ring nuts later this week.

 

I am looking for a 1994 512 TR. Does the diff problem exist in this year model as well? Thought i read in this thread that in 1994 Ferrari changed it to the 512M diff. Did i read that right? Thanks,

 

1. All cars above motor number 31108 have the heavier prop shaft from clutch to main transmission.
2. All cars with transmissions 1513 and above have the forged differential casing and the upgraded differential ring, pinion, dowels, and bolts.
(The transmission number is visible on the rear of transmission, looking from underneath the rear bumper.)

 

Thanks for the info Alex.

 

The diff arrived early this week ...

Very nice unit ! And great easy to use packaging of the shims when you need them.
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where do you get this diff now from or who made it? looks pretty good

 

Looks like the Forza diff!

 

That's a Forza diff from Phil in the UK. And I presume by the comment that he sent it out with a set of his new 'peelable' shims.

 

Correct on both accounts, will post a picture once it's back in later today.

 

Joe, its a Forza diff.

P

 

Thats right Uzz, the peelable shims allow shimming down to 2 thou. Saves on buying a bunch of shims that are not needed.

P

 

thanks phil

very well done as I see it

 

right mel,
but could be that worldwide also an other will do such diffs? that is why I wanted to confirm

also form this side I never have seen phil´s diff - or can you please put a link here to see