When a car is driving around a curve, the outer wheel covers a longer distance than the inner wheel and therefore has to turn faster. The driven wheels, which in decent cars are the rear ones, are connected to each other via the drive train.
If you rigidly connect the wheels, but they turn at different speeds, something is going to break. To prevent this, the differential gear was invented.
If this is not news for you so far, you may skip the informative part of this newsletter and continue reading below at the commercial part. Don't do it out of curiosity, of course, but it's good to know that you might.
For those who don't yet know exactly what a differential gear does, we found this video that explains the function in a didactic way:
But what happens if, for example, you take an exceptionally ambitious turn and the inner wheel loses traction?
Then the differential distributes the power to this wheel and the propulsion dissolves into smoke and mirrors.
To prevent this, sporty cars have a limited slip differential that distributes a certain amount of power to the wheel that still has traction.
This is how it looks on the Dino 246 and most Ferraris:
This video is explainig how a limited slip differential works:
As you can see, all sorts of moving parts are installed. Some of the parts work with friction and can also wear out as a result.
Here, for example, is the differential assembly of a Ferrari 308 with massive pitting on the bevel pinions, which brings us to the subject of oil.
In most of our Ferraris that have the engine at the rear or in the middle, the differential shares the oil reservoir with the main gearbox. If you don't consider this and use standard gearbox oil the diffrential lamellas will quickly be worn and the locking effect gone.
So which oil to use?
The first decisive factor is that it must be an oil of class GL5, which ensures lubrication despite the high forces acting in such gear units.
Secondly, an oil with LS additive is required. LS as for limited slip so you can be sure to have the lamellas protected for wearing out to fast.
If all this is too much for you, you can just get your oil ordered here In the store . (for most countries)
Let's get back to all the multitude of moving parts that can break.
We are looking at pinion and crown wheels plus the parts installed in the diff housing that have mostly been produced by ZF for our Ferraris and Dinos. These are:
- Roll Bearing Differential
- Pinion Differential
- Bevel Pinion Differential
- Inner Lamella Differential
- Outer Lamella Differential
and you're lucky, we have them all!
to be continued...
The documentation of which Differential CPL. was installed in which car is not clear, but we will be happy to clarify everything before delivery if, you tell us the number that is on your Differential CPL.