Differentials available for Testarossa / 512

So what have you guys done about bolts for the crown wheel to the carrier?

Apparently there was an upgrade somewhere along the way, maybe with the 512 TR but I can't locate part numbers for this.

Eurospares list:

bolt 104310 (x 12) at 6.20 GBP per bolt = 74.40 GBP
safety plate (x 6 ) at 12.03 GBP each = 72.18 GBP

Looks like about 150.00GBP for bolts and plates to lock down that crownwheel.

What's wrong with using the factory original bolts and plates. Are they likely to come undone. Locktite super stud retainer compound, original bolts and locking tabs should do it.

Comments and opinions guys?

 

Robert, take a look at SB 30-23, second paragraph.

"Courtesy of Steve Magnusson"

DIFFERENTIAL /TRANS UPGRADES



SB 30-23 describes the new forged differential housing, part number 155099 that was incorporated in the 512TR somewhere around the 1994 model. It replaced the previous welded type. Checking the gearbox serial number will indicate which housing your 512TR has. The SN break is 1370 and later. Another improvement was made at SN 1513 whereas a later ring gear mated to the differential with dowel pins and bolts of finer thread than previously. My 1992 has gearbox SN 314 which is much prior to the forged differential. The SB states that the forged differential will also fit the Testarossa but does not mention the Boxer series.

SB 30-23 also announces a new, stronger bolt to attach the ring gear to the differential. It is the courser thread allowing you to retain the older ring and pinion gear and could be used with either the welded or forged differential. I had planned to install these bolts when I do an engine out early next spring, but my fear is increasing enough about the welded differential that I may replace it also.

SB 30-18 describes a new heavier propeller shaft incorporated in the 512TR commencing with engine number 31108. My engine number is 29896 so this probably occurred in 1993. The propeller shaft is what was previously pictured and referred to as the quill shaft. It transmits power to the transmission from the gearbox attached to the clutch housing. When I had the gearbox off to work on the throwout bearing this shaft slipped right out of the transmission. The female end goes in the transmission and male into the rear gearbox. The earlier shaft was 17 mm diameter while the improved shaft #151651 is 20 mm diameter. If my calculations are correct that is 38% more mass to the diameter of the shaft. The new shaft will fit the Testarossa and the 512BB according to the SB.

I think the above production improvements of the late 512TR's carried over to the 512M with the same part numbers but don't have an M parts book so cannot verify this.

 

This is exactly what bothers me. It appears that the 512M carrier has a different thread to the earlier carrier but you can use your original crown wheel and pinion. With a different pitch thread there is no way you can use 512M bolts on a Testa or early 512TR diff.

So given that info, maybe there is no upgrade to the bolts on a Testa and a prudent installer would merely fit new locking tab plates?

What do you think?

 

I have yet to hear of bolt failure on these cars.
I know this sounds so un-like Ferrari but would the "new" style bolts merely be a pre-emptive design improvement because of the higher HP of the 'M'?......the same reasoning behind the the carrier upgrade?

It looks like you are stuck with the older style bolt.
With that said, prudence says go with all new OEM bolts if you think it's an issue.....................you would be covering all the bases, BUT, I don't think it's an issue on a 390 hp engine..

EDIT: Because of the catastrophic nature of the failure I would not take any chances and spring the extra 100 GDP for added piece of mind.

 

I spoke to a diff specialist yesterday about the bolts and more importantly, the locking tab plates.

He said that after 30 years of installing diffs, he NEVER uses locking tabs and that we should throw them over our left shoulder.

Hardened bolt, hardened crownwheel, hardened diff housing, mild steel locking tab.

He says that it's impossible to attain perfect torque settings if you are pulling down a hardened bolt against a hardened case with a mild steel tab in the middle. It will simply absorb the torque and then release the torque like a rubber band.

He said to just torque up without the tabs, and if you want added security, then use Loctite 270.

I called Loctite but 270 is a UK / Euro designation. Here in Oz it's equivalent is Loctite 263 or for the best yet use 277 which is military grade. It's thick though so you need to push it into the threads with your fingers before screwing in the bolt.

 

Your diff specialist is absolutely right: throw these locking tab plates away !

This UK diff is the result of extensive engeneering and modern thinking: can't be better !!

For that reason I have already commented that I liked the shallow counterbore to accommodate the bolt head !

 

We will use Loctite 270 (42NM) or Loctite 278 (42Nm) when installing my new diff.

The bolt must be changed too (no more neck) ... size: M10x1,25x35 H10.9 , strength 8.8 .

We used 12 bolts of a F BB LM
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Hi Mel,
The normal BB have screws with hardness 8.8 and the LM version 10.9
And your diff have now the 10.9 version with loctite 270.

regards
Andre

P.S. this was the last set of bolts for the LM we have in stock!

 

Thanx Andre ! Show us foto's of your work please !!!

Andre is THE gearbox builder over here, doing mine NOW !

 

That is always the option to "Saftey Wire" the bolts.....Mark

 

I spoke to a rep from Henkel the manufacturers of Loctite and he suggested that 263 is a great product in this application and that if you wanted the best then go to the military spec of 277.

We bought some 277 and gave it a try. On a bolt left overnight we had just started to move it and the harder we tried, the tougher it got. The Henkel dude said that we would probably break the bolt first. I reckon he's right. It got bloody tight!!

So I assembled my diff with 277 and torqued it up to the factory spec with a digital $1000 Snap On torque wrench (borrowed LOL)!!

 

CAUTION >>>>>>>>>>>

We have done two Testarossa diffs in Melbourne this week and both cars have never been apart before. One had broken the diff (mine) and the other car was being fitted as a pre-emptive move.

BOTH cars had warped crown wheels!!!

Both crown wheels were binding on the pinion and did not allow a proper bearing pre-load reading to be taken. Once the rear face of the crown wheel was flattened with wet and dry 1200 grit on a flat plate or glass, then both diffs came up perfect.

Rule here being.....flatten your crown wheel before fitting it to your new diff when it's time for replacement. It appears that factory torque settings can pull the crown wheel a little and cause it to bind. This may only happen when it is removed from the diff, no way for me to tell this.

 

MAYBE we have discovered a very new factory fault !!!!

Warping may cause the destruction of the pinonwheel ..... and that's happening all the time TOO !

Beware .....

 

Also measurements on my old and damaged crownwheel show "bends" !

It is horrible to think that this is reallt Ferrari quality ............

 

Forgive me for waking up an old thread, but I have searched elsewhere, and I believe these questions were not answered that I can find...

1. Has anyone a general idea of an approximate cost in the USA for the labor to install one of these complete UK diff's from Phil into a Testarossa which has not had any problems yet?

I intend to do this as a preventative measure, and would like to get an idea of a general range on hours of labor, or cost, or both.

2. Does this have to be done by a Ferrari person, or is this the same as the procedure for setting up the differential in any mid engine car?

3. Would the cost be more? or less? with a 512TR as opposed to a Testarossa, everything else being equal? (# of hours for shimming, etc)

4. Is this the type of thing where it would be cheaper to do if the motor was already out for the major service?

5. What is the complete list of parts needed for the job of replacing the unit preventatively, in a low mileage car that has had no troubles with the diff or trans?

I am assuming,

The diff itself $1850 GBP
Bearings $82GBP/side
Shims (I see these cant be sourced from Ferrari due to unavailability and cost)
various gaskets?
Bolts? (can ARP supply these? or reuse original bolts?)

6. Phil talks about setup of the unit. What do I tell him for clutch pre-load, ramp angle and numbers of clutch plates? I just want a standard replacement, no racing stuff. Something most closely resembling the original unit. I baby my cars. I only use them for grand touring and doing errands.

7. Will this aftermarket unit act and perform the same as the original unit, or will it be an obvious change?

Thank you very much everyone, for all your generous time and input on this forum. I am sure this forum saves people many tens of thousands of dollars.

Oh, damn, one more question...

8. Is there any market for the used parts that come out, if they are in undamaged condition? What are these parts worth if anything? (I here that people who use the Newman carrier need to get innards from somewhere, so maybe they could use mine, or maybe the whole unit has value?)

Thanks again

Andre

 

Whew, let's see if I can answer a few if not all these for you,

Labour will depend on your Mechanic and his rates and competency level. If he's done Ferrari diffs before then it's pretty straight up.

My diff fitted perfectly, and another one done in Melbourne was also no issue to fit.

Not necessarily a Ferrari mechanic, but they do need to be skilled and versed in setting up a diff preload and backlash according to the factory settings. It's not that difficult, I did my own.

Same cost for a 365 / 512 / Testa / TR / M. All the same diffs.

Yes, definitely cheaper to do when engine is out. But can be done in the car also.

Diff, bearings, shims, seals, some sealer, oils.

Bolts, you can reuse your own, buy from Ferrari, or just buy quality bolts from ARP or a similar supplier.

I had mine setup for road use and also the other one in Melbourne the same. Feedback is that the car will feel absolutely zero difference, although it may improve a bit if your backlash was already a bit opened up on your original diff.

Your old welded diff has limited value because we all know that it will break one day. However, when mine broke, the innards also were damaged so I was not able to use a Newman diff. In that case you could sell your innards but the market would be very small. Anyone with damaged innards would generally just buy a brand new complete diff from Forza .

 

It's funny this thread came up again, because I was thinking about it earlier today, and wondering if there had been any follow up on Melvok's theory about the warping ring gear? Did I miss it?
I'm hoping to finally take the plunge next year and get either a Testarossa or 512TR. Of course I plan on upgrading the diff, but I'd like to know if I need to plan on updating the ring and pinion too (if I remember correctly, Newman makes those too).
Thoughts?

 

Thanks for the comprehensive answers I really appreciate it.

Perhaps I should have asked "approximately how many hours of labor for the procedure?" rather than asking about the cost of labor. Of course that varies because of the rate. Luckily my guy only charges $100/hr, and he is the definition of competence, skill, and honor.

 

Mine was 40 hrs work but that was at € 45 per hour and including changing all bearings .... $ 100 seems not cheep or am I wrong informed ?

And now ? Better than new !!! Never shifted so neasy and no yarning in any gear at all ...

The good thing when taking apart the gb at an engine-out is that you then can inspect the other gears the best.

Don't miss bad teeth ..... exchange them also right away before bad things occur .....
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I have stumbled on a supply of OEM NO weld cover complete LSD-they are not mine, I am not peddling parts, but am happy to respond to PM for those wanting OE and willing to pay the significantly higher price for them-the billet items shown in this posting are outstanding workmanship and would use them myself-however, many owners prefer ZF original stuff, no problem, like I said, PM me if you prefer and are inclined to pay the significantly higher freight for OE
FWIW...it was an odd stash to find...

 

Quite surprised .... I had to look in the "whole F wordl" and no F shop/dealer could find them .....tell us more than this .....

And please show us photo's please ...

 

I see that now the diff that we so successful fitted in my 512TR is also for sale in the U.S.A. at Ricambi !
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in 2006 I got 1 diff from the US, this has been made by MODENA ENGINEERING in australia.

I let manufactured 2 more diffs there in 2009. those look very very good but until now I was not driving anymore, so I can not say if those are reliable or not. but may be one of you have experiences?

one gearbox meanwhile is in the car again, a second gearbox I just work on and the 3rd is still waiting to get started with

the first picture shows the original broken diff, the 2nd one the broken gear and the other 2 are the new diff
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Ask Andree of BB-motors in Bremen / Stuhr ! He is an absolute expert ! (I have his info if needed: [email protected])

 

"Yes, definitely cheaper to do when engine is out. But can be done in the car also."
was posted by uzz32soarer.

I recall a thread where a TR diff replacement was attempted as a safety precaution (no failure), and after getting in there, and trying to Rubik's Cube it in some orientation to get it out, the effort was abandoned and put it all back together.

Was this a case of getting cold feet at the finish line, or did the motor need to be loosened from its mounts and lifted (which IIRC was tried) etc? Maybe lifted more? OR some cars just aren't built so that it can be done? Chassis variability etc?

I drive my car pretty gently and I'd need all the money I could save for therapy if my tranny junked itself.