Broken Transmission

Boy, is it appropriate that "Damaged" responded to a thread on a "broken transmission"!

How often does that mix occur?

 

I only just spotted this thread...

Brian, I've not seen a gear fail like that in any race 360....... yet

It's got ABSOLUTELY NOTHING to do with the tyre, in any way, shape or form. That failure is due to component failure and/or (more likely) abuse, without any doubt whatsoever.

The 360 challenge and GT cars all use the same road spec/quality gears, and they of course use racing slicks and are subjected to much greater loads than normal road use... but significantly, race cars don't do burnouts or circles while bouncing on the rev limiter. Also, they only weigh between 1180 and 1300 kg with driver, so maybe that helps a little bit.

Here's a few pics of boxes and failures.

You can see one Michelotto 2nd gear with small chip with new part alongside
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Alright FFixer...I got some support...
http://www.ferrarichat.com/forum/showpost.php?p=136177409&postcount=63

 

... Quick thread resurrection...

What's the verdict on rear tire width and the gearbox? I was thinking of going 325 on the rear (no track use, no craziness) but not at the expense of the gearbox / driveshafts.

 

I'm so glad someone resurrected this thread!

The pics of the sheared inner diff shaft is EXACTLY WHAT HAPPENED TO MINE! There is an available non-published superseded part which was solid instead of hollow at the taper. This prevents it from shearing at the taper.

I replaced it myself in a few hours.

So to reiterate, Ferrari changed the inner differential shaft from a hollow unit to a solid unit during the production run on the 360 without issuing a notice of it being superseded.

 

Was this due to running a larger rear tire??

 

What problem are you trying to fix with the wider tire?

 

No no, I just aesthetically want to run a 325 but there were reports of wider tires being too harsh on the gearbox etc... that was years ago... So I was only trying to determine if anyone else had seen similar issues.

Not trying to fix and issue just not cause one

 

*Not trying to fix an issue, just not cause an issue....

 

With larger wheels and tires you are not only stressing the drivetrain, but also the wheel bearings.

 

I see - then the first things I would consider are rubbing, balance, ABS and tire selection/availability.

If you go 325 in the rear, you probably want to go at least 255 in the front. That might be a tight fit.

 

Not sure. I do know that the replacement part I ordered was exactly the same from a distance; but when you looked into the hole, the solid portion extended about 1-1.5 inches further out toward the flange, increasing its strength.

I do have 20" wheels, but considering this is the same part used in the Maserati that comes stock with 20" wheels, it had no connection.

 

Personally, I don't quite understand the relationship between larger wheels and gearbox problems. The the only thing that can stress the gearbox is in increasing the height of the wheel/tire, which would cause a slightly larger load when accelerating and would drastically affect the speedo/odo. Typically, when you increase the wheel diameter, you reduce the sidewall height to accommodate. If there is any variance, it should be minimal. The weight of the 19" tire/wheel vs. the 20" is nearly identical and sometimes is, unless you're running steel wheels. As for the extra spun weight, if the transmission was that sensitive, you may want to ask your passenger to skip lunch before riding shotgun because the transmission knows no difference between loads at the shaft, unless the car is off the ground.

And yes, I ran 325 30 19s on my Maserati F1 for 135K miles with no issues. That shared the 599/612 transaxle.

Anyway, the reality is that telling the difference between correlation and causation is nearly impossible in my experience.

 

I have 305s in the rear and don’t have any issues. I have not personally taken the gearbox apart and inspected all parts first party, but the rims have been on the car since 2006. 2nd is a little notch but I think that’s a small part in the linkage I need to replace next gearbox flush.

 

Try putting progressively wider tyres on, which increases traction, and see what fails.
If it's just for the look and not for any performance upgrade then no problem.